Archive for the ‘Drainage Systems’ Category

Condensation in a manufactured home crawlspace with “ventilation”

April 27, 2011

So, your brand new home was built with a crawlspace that has the vents installed according to code requirements. Further, the crawlspace has a proper vapor barrier covering the floor. You should have absolutely NO concerns about moisture in the crawlspace, right? Well, maybe.

Here is one case where I found out in a rather uncomfortable way that a crawlspace built with proper ventilation and a moisture barrier (of sorts) can indeed get lots of moisture.

One spring day last year, I left a meeting in Columbus around noon and headed toward Wilmington to do an FHA inspection on a new manufactured home installation. This home was built on a crawlspace with a poured concrete slab floor. The home’s air conditioning was not operating because it had not yet been fully installed. Wilmington had received light rain the morning of the inspection. The home reportedly has had drainage problems at one end; but the crawlspace was dry. By the time I got to the home, we were experiencing our usual humid weather our springs and summers bring.

Let’s get into the photo (fun) part of the story.


This photo shows a front view of the home on the day of the inspection. Note the right crawlspace perimeter wall.



This photo shows a closer view of the right perimeter wall area, which was still having some drainage problems on the day of the inspection.



When I went to enter the crawlspace, this view greeted me. Note the water droplets hanging on pretty much every surface in the crawlspace; but the slab is totally dry. BTW, that metal bar angling from the slab to the home’s frame is a lateral brace—part of the home’s anchoring system.



In a view down the crawlspace, water droplets can be seen on pretty much all surfaces.



And since I have a lot of pictures, here is yet another view of the water droplets on surfaces. The lateral brace in the photo is the second of the pair of braces used in the anchoring system. Note all of the droplets on the bottom board (the membrane along the bottom of the home.



This photo shows a closer view of water droplets on bottom board—and by this time on my camera lens.



Yep, a lot of water was present. And every time I raked any of these surfaces, I got a shower of cold water—not a pleasant experience.



This photos shows that the crawlspace vents were wide-open. Interestingly, no surfaces near the vent has water on them.


Where am I going with this story? All of the water droplets seen in these photos are due to condensation. The prior night, the area where the home was installed had colder temperatures and, since the home was not heated, the crawlspace temperatures were also on the chilly side. The next day, as is common in our area, outdoor temperatures climbed rapidly, as did the humidity levels, fueled in part by recent rain. The crawlspace surface temperatures remained below the condensation point of the air, causing water droplets to form on pretty much every surfaces inside the crawlspace, except those near the vents where the surfaces apparently warmed more rapidly.

I believe that this case is proof that even properly ventilated and moisture protected crawlspaces can get water in them. The condensed water may have come from water vapor coming up through the slab. However, the open vents provide a more open path to water vapor in the outside air.

Even if water vapor had come up through the slab, this case shows that the water vapor can be converted back into water droplets that can be absorbed by the crawlspace materials exposed to the water. Thankfully, the intact bottom board of this manufactured home prevented moisture from reaching the insulation above the bottom board. Otherwise, the insulation could sop up the water like a sponge and hold it long enough to possibly cause more serious issues.

However, this case shows that water can get inside a crawlspace without liquid water entering the crawlspace. If surfaces inside the crawlspace are below the dewpoint of air entering the crawlspace, condensation will occur. Having vents in the crawlspace open it up to outside air which can supply the moist air. Open vents can also allow heat in the crawlspace to escape, allowing surfaces in the crawlspace to cool to below the dewpoint temperature of air that may enter the crawlspace later.

Now, if the crawlspace does not have a vapor barrier, moisture issues could be much worse. I am looking forward to the time when I enter a crawlspace that actually has fog—and I have been in some that were close.

Oh, one other lesson I learned is that if you are going to enter a crawlspace with condensation on the surfaces, you will get wet. In this case, I was soaked to my underwear by the time I left the crawlspace. Very unpleasant.

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Want Proof That Termites Are (Misplaced) Evil?

April 15, 2011

I recently had a structural inspection that showed (once again) how much damage a gang of termites can do to a home. This damage was located in the rim joists and sole plates of a home with brick veneer. However, these termites had incentive to invade the wood due to the rim joists and sole plates being apparently exposed to excess water coming from behind the brick veneer.

Some background is needed before getting into the termite business. The sole plates are the boards that sit atop the foundation, upon which the first floor joists rest. Rim joists, also known as band joists, are the boards that box in the floor joists. The ends of all floor joists resting on the sole plate but up against rim joists. Rim joists also help stabilize the joists and help keep them from angling or twisting.

In a properly designed brick veneer wall, a gap is supposed to be installed between the brick veneer and the exterior wall sheathing. The exterior sheathing is the material that covers the outside face of the wall framing. Sheathing can be boards (in older construction), or plywood or oriented strand board (OSB) panels, although in some construction Styrofoam panels may be installed between the plywood or OSB panels. The gap between the exterior sheathing and brick veneer is supposed to serve as a drainage plain to provide water that gets past the brick veneer a drainage path to the base of the wall. And, believe me; water can get past the brick veneer, particularly if the brick is especially porous. Drainage holes (in combination with flashing) in the brick veneer just above the foundation in the brick veneer are supposed to provide a path for water to flow out of the drainage plain. Brick veneer installed on concrete block construction, more commonly used for commercial construction, is also supposed to have a drainage plain with weep holes.

Full brick exterior walls, such as those on many old buildings in Cincinnati, do not need weep holes because the water supposedly travels fully through the brick into the interior wall surface or back out to the exterior surface. Another brick construction that was usually not built with drainage holes was concrete block on a concrete foundation with brick veneer installed in front of the block. Unlike the previously described brick veneer/concrete block wall, the first floor framing in this construction was built on the block and the upper floor framing was built above that. The brick veneer in this construction extended from the concrete foundation and up the exterior wall. This last construction, as used for a crawlspace construction, is the subject of this blog post.

Let’s start with a photo of the foundation construction from inside the crawlspace, shown below:


This photo shows the concrete foundation with the concrete block above it. On the exterior side of the foundation, the soil level would be to the top of the first row of concrete block above the foundation. Now, take note of the dark streaks on the facing concrete foundation. Those streaks are due to water drainage through openings in the block mortar. The question is from where is that water coming. For sure, water can migrate from the soil through the block. But, the darkened block in the area in the corner area and along the foundation to the left that extends the full height of the block hints at another source—the drainage gap behind the brick veneer. Darkening of the block indicates that they are water-saturated. Further support for the drainage gap being a water source is evident from the darkened sole plate wood sitting on top of the darkened concrete block.

Let’s take a closer look at part of the area along the facing foundation. Note the copper water pipe in the photo above. This pipe is the same as the one shown to the left in the photo below. In this photo, the darkened woods of the sole plate and rim joist above the water-saturated concrete block is visible. However, also visible are darkened areas in the subfloor boards on top of the joists. The material that looks like resin or droplets is water droplets on the wood surfaces. The pattern of the water stains on the subfloor indicates that the water source is the exterior wall, and more particularly the drainage gap behind the brick veneer. Areas like these were found all along the exterior walls of this crawlspace foundation.


So, what do these findings have to do with termites—as it turns out, a lot. Termites are one of Nature’s maintenance creatures. They reduce wood back into a form that is useful to plants, microflora and soil. The trouble is that they cannot distinguish between the dead wood of a tree in the forest and the lumber we use in our buildings. The subterranean termites we have in the Cincinnati area also require water to live. In fact, they build mud and frass tubes in areas where they would be exposed to air to conserve water and will carry water from the soil into the tubes to keep them damp enough. In the photo below, the dark streaks on the foundation are the remains of such tubes between the ground and the sole plate. Note that the distance between the ground and the sole plate in the photo is about 5 feet. Termites can be very determined to find a food source.


If termites can find wet wood, their job gets much easier because they do not have to bring as much (if any) water up from the ground. So, in the case of this home, they found it in the wet sole plate and rim joist woods. And once they set up their work area in them, they went to town. The following photos show some of the visible damage. Note in all of these photos that the wood is darkened due to water exposure.




I want to emphasize the words “some of the visible damage.” The exact extent of the damage generally would only be known when the damaged wood is removed and inspected. An ice pick or awl can be used to probe the wood and somewhat determine the extent of damage. If the damage is on the other side of solid wood, though, this method would not find it. Also, termites form multiple tunnels in the wood, which means that unless the wood has been greatly degraded by the tunnels, as in the photos, a lot of probing would be needed to fully determine the damage. More sophisticated and expensive methods to determine the extent of damage exist, such as injecting chilled or heated air into the termite tunnels in the wood and viewing the wood using a thermal camera. In theory, the air would follow the tunnels and provide a temperature difference within the wood that is visible to the camera. The common method, however, is using a probe.

The damaged wood in this home will need to be removed, which will be expensive due to where it is located. The repair will also not be as ideal as new construction. Even worse, as wood is removed, more damaged wood that is not readily visible might be found, making the project much more expensive.

But, a question still exists as to why the sole plate and rim joist wood is getting wet when the wood is at least 16 inches above outside grade. Additionally, the drainage plain behind the brick should extend below the wood to the concrete foundation level. I believe that a couple of possibilities exist. The brick might not have a proper drainage plain, in that the brick veneer is right up against the exterior sheathing. I hope not because that likely means the exterior sheathing and upper floor framing could have moisture and/or termite damage. Another possibility is that the rim joists and/or sill plates block the drainage plain. Then again, water from the upper drainage plain may be filling up the concrete block and/or the gap between the brick and block to the level of the wood. Overall, though, the fact that the subfloor appears to be getting wet indicates that a drainage plain issue is present. When the wood is replaced, the real water source might be evident.

What are the morals of this story? Here are a few:

  • Damp crawlspaces or basements can be an invitation for termites to move in.
  • Properly designed and installed drainage plains behind exterior finishes, whether brick veneer or siding, can help prevent expensive repairs.
  • A great amount of water can penetrate through brick.
  • Trick observation—the crawlspace floor was muddy apparently due to water flowing into it. Since no vapor barrier was present, water from the wet soil can evaporate and enter the home where it can cause mold growth in those dark and quiescent locations where mold likes to hang. Then again, even a vapor barrier might not help if too much water is getting into the crawlspace.

Unfortunately, like most projects of this kind, I will not know the outcome due to the nature of these kinds of projects. Be assured that if I hear anything, you will be the first to know.

Sump Pump Systems Revisited

November 21, 2010

I recently came across a sump pump installation during a home inspection that caught me by surprise–and that takes some doing.  Below is a picture of the pit.  So, what was wrong with this sump pump pit installation in the following photo:

A sump pump pit in a home that I was inspecting.  What is wrong with this installation?

Hopefully, your answer is that the pit was constructed of cardboard.  More accurately, the pit was constructed using a concrete form tube, such as Sonoco’s Sonotube brand (http://www.sonotube.com/sonotube.html) or Quikrete’s Quik-Tube brand (http://www.quikrete.com/productlines/QuikTubeBuildingForm.asp).  For those unfamiliar with form tubes, they are thick-walled, multi-layered cardboard tubes that are used for rapidly constructing concrete forms primarily for column piers or foundations.  They have been a boon for structural construction in that, when a pier is needed, say to support a deck column, the installer only needs to dig a hole large enough for the form tube, (hopefully) install a footing or compacted base material, place the tube in the hole with rebar if needed, and pour concrete into the tube.  (I have also heard that form tubes make a wicked impromptu drum.)

For the installation in the photo, the form tube was used as a sump pump pit.  It appeared to have been installed a number of years after the home was built.  The basement in which the pit was installed had apparent moisture intrusion issues, which I concluded were  partially due to the water drainage for several adjacent properties being run within 20 feet of the basement.  The installation indicated that a hole had been made in the basement’s concrete floor and the sub-slab soil removed to a couple of feet.  Then, gravel appeared to have been put in the bottom of the hole and the form tube installed and concreted in place.  As the photo shows, a drain line is run through the side of the form tube, although from where it came could not be determined.

So what is wrong with using a cardboard tube for the pit.  The darker tube area deeper in the pit is the clue.  This part of the tube is saturated with moisture, even though a number of weeks had passed since the area received measurable rain.  I was able to stick a screwdriver blade through the darkened area of the tube, verifying that it was wet and degrading.  Over time, the cardboard will likely completely degrade.  As that happens, soil around the pit will erode into the pit decreasing the pit’s depth.  Erosion of the soil will also create a void under the slab and quite possibly under the nearby foundation.  And then, the home has great risk of structural issues that will be expensive to fix.

But, degradation of the pit and potential structural issues are not the only problems.  Water flowing into the pit is also likely not contained within the pit.  Instead, it is flowing out of the pit into the soil under the basement slab.   The lower part of the tube still being wet despite no rain for awhile shows that the soil at that level is also wet, which was verified by the mud on the screwdriver blade when I withdrew it.  Water in the soil below the slab will wick throughout the soil up to the slab.  If an adequate vapor barrier was not installed below the slab, water vapor from the soil can flow through the slab and into the home, causing moisture issues inside the home. Even if the sump pump removes the loose water under the slab, as the cardboard shows, the soil will still hold water because that is what soil does.  This moisture will eventually evaporate to water vapor, which could flow into the home through the slab if an adequate vapor barrier is not present.

And what happens if a LOT of water is flowing into the sump pit through the drain line in the photo?  In this home, cracks in the slab had been sealed, which may have been precautionary.  On the other hand, water could have percolated up through the slab already.  A large volume of water flowing into the sump pit and under the slab could lead to water flowing up through cracks in the slab, even if a vapor barrier were present.  Water could flow out of cracks in the slab without coming out of the sump–water seeks its own level and the top of the slab around the cracks could be lower than the top of the slab around the sump pit.  If this drain line is carrying water from around the exterior of the basement foundation, there could be a LOT of water, especially if water from nearby properties is being channeled near that basement wall.

Water flowing into the sump pit will also be carrying small soil particles.  Although soil particles being present in groundwater is normal, if that water is flowing from an area prone to soil erosion, the amount of soil particles could be greater than normal.  These soil particles are sucked into the sump pump with the water.  In turn, these soil particles erode the pump’s impeller, the part of the pump that moves the water .  Erosion of a pump’s impeller shortens the pump’s life, meaning that the pump would need replacing more often than normal.  (Note that for most pumps, replacement is cheaper than trying to rebuild them.)  Erosion of other materials inside the pump likely also occurs, decreasing the pump’s efficiency.  That is, the same amount of electricity is being used to run the pump; but the pump is not moving as much water for the amount of electricity used.  You pay the same amount for the electricity, but get less for it.  BTW, if you have not priced a sump pump lately,  they start at about $125 just for the pump–plumbers, if needed, are much more expensive.

For the sump pump system in the photo, it will need replacing.  Hopefully, a proper durable sump pit and pump will be used.  I also hope that the person who installed this sump pump system is not the one hired for the replacement job.  The homeowner assured me that person will NOT be the one they hire.  I just hope that no one else has hired him/her for their plumbing work.  Sump pump systems seem like such simple things, and they are to an extent.  However, they are very important systems for keeping a home high and dry.  They should be given the priority they deserve.

Water that foundation

September 18, 2010

Well, I don’t mean literally.  Actually, I mean that sometimes homeowners need to water the soil around the foundation.  Here in the Cincinnati area, as with many other areas, we experienced a very wet spring.  Then, Mom Nature, apparently fearing that she might mess up the averages, pretty much completely shut off the valve.  We are now nearly 6 inches below average on rain–and our clayey soil is rock-hard dry.

One of the characteristics of clay soil is that it shrinks significantly when it dries.  You might have noticed such shrinkage in the gap that has opened between your foundation and the soil.  Keeping the soil evenly moist around the foundation helps prevent or even prevent shrinkage.  However, when watering the soil, don’t just water a narrow band of soil.  I normally recommend watering a band of about 6 feet.  Now, 6 feet is not a magical width; I just mean to water a wide enough band.  If you water too narrow a band or soil, the surrounding ground will suck up the water rapidly, essentially countering your good intentions.  You should also not spray water directly on the foundation, which is never a good practice.

How much to water depends on the soil composition, type and conditions.  Checking the soil using the old finger probe similar to the way you would check the soil in a planted pot is possible.  You just push your finger into the soil to a depth of about an inch and, if the soil feels damp to your finger, it is probably wet enough.  Then again, not being able to push your finger into the soil probably also tells you that the soil is too dry.  You can also use the simple plant moisture meters available in many stores for use on potted house plants.  If you want to get real sophisticated, soil moisture sensors that actuate an irrigation system are also available.  You can find these by Googling “irrigation soil moisture sensors”.  Creative homeowners who don’t want or can’t have an irrigation system installed around their foundations should be able to make up a system using soaker hose, the moisture sensor and control system and an irrigation valve.

So, what is the big deal about the soil being too dry around the foundation.  (Truth is, maybe I should not even be telling you this preventive measure because in the past, we have had a lot of jobs from homeowners because of this issue.  But, that is not our way.)  First and foremost, the foundation can settle and develop cracks and some of these cracks can be severe.  The most common reason for cracks is that the foundation settles unevenly, which is a particular problem with the type of foundation that everyone wants nowadays–the walk-out basement.  Heck, I like ’em too, even though I don’t have one.  With these types of foundations, the soil may be dry to the same depth all around the foundation; but the soil around one part of the foundation may be dry to below the depth of the footing while the soil around another part of the foundation is not.  Dry soil shrinks; so some of the soil around the foundation shrinks while it doesn’t around the other parts.  This condition results in part of the foundation moving while part of it doesn’t.  And that difference in movement can result in cracks.

Besides walk-out basement foundations, stair-step and concrete block foundations (both of which may also be a walk-out basement foundations) are especially prone to developing cracks under uneven soil drying conditions.  Another susceptible foundation construction, which is VERY common, is the crawlspace, stem wall or porch foundation that is poured continuous with, but which is much shallower than, a basement foundation.   The same logic can be used to explain why cracks could develop.  The shallower foundation settles while the basement foundation doesn’t.  Basement foundations that are not walk-out types, stem wall and crawlspace foundations aren’t totally immune from developing cracks either.  The conditions dictate the development.

Slab on grade foundations are also susceptible to developing cracks in the slab, depending on the slab construction.  In the case of these slabs, the soil around the outer edges of the slab could dry while the soil farther under the slab dries slower.  In this case, the soil around the perimeter of the slab shrinks while the soil farther under the slab doesn’t.  The perimeter of the slab settles, while the parts farther under the slab do not.  In this case, the slab might develop cracks as well as heave.

The second reason is that what does down might need to come back up.  Just as clayey soils shrink when they dry, they re-expand when they moisten.  If the foundation settles due to dry, shrinking soil, the foundation might not move back the same way when the soil moistens and re-expands.  In moving back with the expanding soil, the differences in the amount of movement around the foundation could occur, creating stresses that cause cracks.  The soil also might have shifted and exerts pressure on the foundation differently than before.  Soil that shrinks may not re-expand as much as it shrank because the spaces between the soil particles are squeezed reduced as it shrinks.  When the soil re-expands, the spaces between the soil particles might not be the same as before, causing stresses that create cracks.

A third reason for keeping the soil around the foundation evenly moist is one I hinted at earlier in this post.  The gap between the soil and the foundation becomes a water channel when it finally rains.  This issue is a problem mainly for basement foundations.  Don’t let anyone kid you, nearly all foundations are porous to a varying degrees, even those with some exterior water barrier coatings.  Water running down the foundation wall is absorbed by the foundation materials and transferred to the inside of the foundation.  If the foundation happens to have a crack in the right place, the water will have an open path through the foundation wall.

Water that isn’t absorbed by the foundation materials or doesn’t flow through cracks can cause issues around the foundation by eroding soil around the foundation.  In most areas, building codes now require that homes have a foundation drainage system.  Those systems work to capture a great deal of water around the foundation IF they are installed properly.  On the other hand, water has a mind of its own and seeks the path of least resistance.  Therefore, the water might choose to flow under the foundation and not into the foundation drainage system.  If enough of it travels through one area, soil erosion can occur, causing the whole uneven foundation support thing, which can case cracks, and/or worse shifting, of the foundation.

A final, not so directly an issue, is loss of vegetation around the foundation.  In particular for homes built on hillsides, loss of vegetation could result in loss of soil erosion control.  With soil erosion could come soil sliding.  Cracks in dry soil could also open channels to deeper soil layers that are not as well bound together as the upper layers, resulting in slides.

A couple of other things should also be kept in mind.  The foundation may not the only thing that has moved when it settled.  Everything sitting on the foundation might have also moved.  Foundation movement might be imperceptible but still be enough to cause cracks in other interior and exterior building materials. Further, movement is greater higher up in the building, which means that cracks might be found in upper floor materials without be found in lower floor materials.

Another thing to keep in mind is that movement creates stresses in the foundation and other building materials.  Those stresses might not cause cracks right away.  Those stresses could still be present only to cause cracks later on, such as when another condition creates additional stresses—the old straw-camelback syndrome.

I have thrown a lot at you in this post—and without pictures.  (Over time, I promise more pictures.)  The issues can be complex.  Still, they do not mean you need a structural engineer to look at every crack.  If you have doubts, then hire an engineer to check things out and hopefully provide assurance.  On the other hand, you might try keeping the soil around the foundation evenly moist and avoid having the need for an engineer.

A picture is worth a thousand words

September 13, 2010

A picture may be worth a thousand words; but a picture is also much better than a human memory.  As related to my business, I am referring to whenever a homeowner has work done on their home.  Time and again, I have had homeowners tell me about former work that was done to the home or its surrounding grounds.  Shortly after my questions begin, their memory of exactly what was done stops.

Now, I don’t blame the homeowner for not remembering.  In many cases, he or she trust that whoever is doing the work will do it well and right.  (Well, not always and that is a subject for another blog post.)  In other cases, the homeowner did not exactly understand what was being done and did not pay much attention to what a contractor is doing.  In still other cases, the homeowner may have been very observant of the work, but seen it through different eyes than I would as an engineer.  The result is the same–pretty shaky details.

I will give an example.  A home has trouble with water running out from under a sidewalk and curb and onto an asphalt parking area.  Water running onto asphalt is never a good thing because the water degrades the asphalt and shortens its life.  I was told a drain line was installed.  The problem was that the homeowner did not remember whether it was a drain was only for the gutters or whether the line had holes to also drain the soil.  The difference is important because it could either be the source of the problem if done one way or be a solution for the problem if done another way.  Furthermore, the homeowner could not remember exactly where the line was run relative to everything else.

With the age of digital photos and the prevalence and price of decent cameras, photos are cheap and can be made readily.  You can also take a bunch of photos and they will all have date codes.  And folks, please, please, please don’t use the camera phones to take the photos unless that is the only camera left on Earth.  Camera phones do not have the resolution of the digital cameras or the features, such as image stabilization.  I also recommend that you take photos with the highest resolution camera you can get.  I normally use a 12 megapixel camera.  The reason is that the more megapixels a camera has, the more a person can zoom into the picture to pick out fine details.  I have had to use this feature on many occasions  when trying to dig out details.  I also recommend that you take all photos with the flash on rather than with the camera set to automatic because the flash can highlight some details, even on sunny days.

So, how often should you take photos during the work?  At the least, I recommend photos of before work has begun and when demolition is done or when the dirt is removed depending on which is applicable.  Other times to take photos depends on the work progress.  Maybe the best recommendation would be at the end of every work day because work can progress rapidly.  Any time the contractor states that a change in plans has occurred would be another.  If in doubt, call us and we might be able to provide ideas.

And, what should you take pictures of?  I think one person said it best.  Paint the area with pictures.  In other words, take enough photos to show a complete picture.  Whichever way you have to look to see the work that was done, take a picture.  Be generous.  But, also be sure to review the picture in the camera view screen to be sure the shot is acceptable.  To do so effectively, you may need to go into your camera’s menu functions and change the time the image stays on the screen.

Once you have those photos, do not just put them on your computer or leave them stored in your camera.  I have learned over the years that hard drives are not the most reliable things.  I have also learned, through others thankfully, that laptops  can be stolen very easily.  Cameras also seem to sprout legs and walk.  I recommend that you store the photos on a dedicated SD card, thumb drive, CD or DVD.  In addition, I recommend storing them online through one of the many storage areas because I can tell you from personal experience, it works.  I personally use Mozy and like the service–but you may find others acceptable.  Flickr is a freebie for a certain amount of storage.  Most on-line storage services are quite reasonable for not only photos, but also for the other important documents on your computer.

Again, Criterium-Cincinnati Engineers provides service.  Although we like to earn money, nearly as much as the guys who like to receive money from us for their services.  That does not mean we charge callers for every phone inquiry.  We don’t and we don’t do the hard sell.  Call and discuss what is going on with one of our engineers.  We will be glad to help.

Home drainage

February 10, 2010

If someone were to come up to me on the street and ask me, “Hey Matt, what do you consider to be the top five problems with homes?”, I would definitely have to include drainage as one of those five.  However, drainage problems have many causes.  Some are due to improper control of the roof drainage, while others are due to improper sloping of the ground around the home. The thing is the severity of these kinds of problems are highly under-rated by most homeowners.  In many cases, fixing drainage problems could stop or severely reduce water intrusion through foundation cracks.  For those with concrete block or stone foundations, fixing these problems could reduce moisture intrusion through the blocks, which is a chronic problem with most block and stone foundations.

Well, I just happened to have an e-letter arrive in my inbox this week with a link to a very nicely illustrated and explained article about site drainage.  I believe it explains a lot and could be very useful to those who have drainage problems, and even those who think they don’t.  Here it is:   http://www.greenbuildingadvisor.com/green-basics/water-management.

More on our “new” paving ideas

February 3, 2010

I was watching a program on NOVA this evening titled. “Ghosts of Machu Picchu”.  In one part, the narrator was describing a main plaza.  Excavation had found that the plaza had a top layer of soil, under which layers of sandy soil and white granite were placed.  The granite was chips from granite blocks the Inca had used to build the city.  From there the water was directed to fountains and irrigation.

We are so brilliant in coming up with our new paving options.  While the Incas had already come up with the system centuries ago.  We prove once again that our discovery is actually rediscovery.

The lowly window well

January 1, 2010

Let me start out right away by saying that I am NOT a fan of windows in basement foundations, UNLESS the basement was intended in the original design as living space.  Windows in the latter case are usually larger and in many cases intended to be alternate escape routes during emergencies.  These windows are also usually insulated glass and of a better quality.

Windows in the former case are usually relatively small and are usually single-pane and relatively cheap.  I guess they are supposed to offer some light into the basement and, since many can be opened, are apparently intended archaically to provide basement ventilation.  They don’t, particularly in the modern home.  I am especially not in favor of basement of cheaper basement windows because they are a security hazard.  As cheap as most are, they could be easily compromised and allow a route for an unwanted to enter the home.  If you think someone could not get int through the window, think again.

So, what does that discussion have to do with window wells?  Pretty much every time I perform an inspection on a home with below-grade cheaper basement windows, I find water stains on the foundation wall beneath the windows, indicating that water has leaked through the windows.  In these cases, water in the window well has gotten deep enough to partially submerge the window and then enter the basement around or through the window.  If this problem happens often enough, windows with steel frames will rust through and windows with wood frames will rot.

Let me step back and talk about the basic construction of a PROPERLY installed window well.  Window wells provide a space around the window to let in light and provide adequate room to maintain the window.  (Most require periodic painting, window replacement and possibly caulk.)   Most of the current window wells are a plastic or galvanized metal, and form a semi-circular space around the window.  However, I have also seen window wells constructed from stone, concrete block and wood.  Most window wells are 18″ to 24″ deep.

Manufactured window wells are supposed to be fastened to the foundation wall and should be caulked to prevent water intrusion through the gap between the well and foundation wall.  The well wall should be above the grade at least three to four inches; but it also has be extend several inches below the window opening the foundation.  Note that I did not say the window frame; I meant below the concrete edge of the opening.  If stone or other materials that cannot be fastened to the foundation are used, I believe that landscape fabric with a layer of gravel should be installed over the outside joint between the well wall and foundation to prevent soil entering into the well through the gap.  Just this past week, I witnessed a case where soil had extensively eroded into the window well through the gap between the well wall and foundation, partially plugging up the drain opening.  Heaven only knows how much soil entered into the drain line.

Each well should have a drain, which is usually three or four inch PVC pipe, although I have also seen corrugated, non-perforated drain pipe used.  The drain line should have a screen or strainer to keep larger debris out of the line where it could eventually clog the line, particularly leaves and grass clippings.  The top of the drain should be two inches or, even better, more below the window opening in the foundation, again not the window frame.  Pea gravel should cover the floor of the well to prevent soil erosion and mud constantly splashing up on the windows and foundation.  BTW, NO other drain lines should be run into the window well from elsewhere, ESPECIALLY downspout drain lines.  (I would not have mentioned it if I had not seen it myself.

Now, what about that drainage?  Where should it go?  In many cases, the window well drain line is run to the footing drain.  I do not favor the window wells draining to the footing drain because debris from the window well could eventually plug up parts of the footing drain line, and that drain line is extremely important in many cases for preventing water intrusion into the basement.  I first wrote that they could be tied into the downspout drain lines.  After thinking about that arrangement, I decided that was not a good idea.  If the downspout drain line plugged up, water could backflow into the window wells if their inlets were lower than the downspout drain line inlets.  The best arrangement would be to run a separate drain line for the window well drains.  This line could be tied into the downspout drain line if the tie-in were far enough below the window well drain line inlets to prevent backflow into the window wells.

I emphasized that the opening to the window well drain line should be inches below the opening in the foundation rather than the window sill.  The reason is that in many cases, water leaks into the basement around the window frame, particularly beneath it.  I have seen cases where the window frame has had the dickens caulked out of it on the inside, and just as well seen my share of leaks despite the caulk.  What the homeowner usually does not realize is that on the outside, water has gotten into the gap between the foundation and the window frame.  Over time, this water rusts metal frames and rots wood frames.  Furthermore, gaps in materials form what we call a capillary gap which tends to hold the water in place even after the water in the window well has drained away.

One way to prevent, or at least slow down, water intruding through basement windows is to install glass block windows.  These are basically mortared in place and provide about as much water intrusion prevention as concrete block.  More importantly, glass block windows are more secure than most single-pane basement windows.  If you still want a window vent, they are available for glass block windows.  You can even provide an opening for a dryer vent, just be sure to put it higher in the window to prevent water entering through it should the window well flood.  A word of caution, though, glass block windows CANNOT be installed if the window is an escape route.  Those escape windows are required by building codes.  I am talking about replacing the cheapy, single-pane windows.

Before I leave this subject, let’s talk maintenance.  I have seen my share of wells nearly filled with leaves, grass clippings and trash.  I have also seen small pastures in them; that is, a lot of vegetation.  Creatures also have a bad habit of getting trapped in the wells—usually frogs or turtles, but the latest edition to the cats who run my house was also apparently born, and abandoned, in one of mine.  My point is that window wells need probably as much maintenance as gutters.  They have to be kept clean to prevent debris and vegetation clogging the drainage system.  You should keep them clean if for no other reason to be able to periodically check your windows.  One final note, if I have not convinced you to change to glass block windows, make sure that plantings around the foundation do not block view of the wells.  Should an intruder choose that route into the home, at least make it possible for someone to see him/her.  While your at it, maybe you should check the lock on the basement door.


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