Window Well to the Rescue!

Bedrooms below grade need proper escape and rescue openings (EERO). In the context of remodeling a basement this needs to be taken into account if the rooms we are creating are to meet current requirements to be called a “sleeping room.”

Many older homes that have windows into the basement were never designed for escape and rescue and were there to simply provide light and/or ventilation to the basement.

Since proper escape and rescue requires that windows meet minimum net opening sizes, there are almost always going to be necessary changes to the foundation wall to meet these requirements. Besides the opening size, the bottom of the opening can’t be more than 44” above the finished basement floor. In the picture below you can see the nice escape and rescue window installed for this new basement sleeping room.

Escape and Rescue openings

Escape and Rescue openings

While the height above the floor is OK, the net opening size was only 14″ x 33″ and does not meet current EERO requirements. The absolute “minimum” size for an opening that is 33″ high would be 22″ wide (because the window is at grade it can be a little bit smaller than if it was above grade).

Once we have made our opening and that opening is below grade, window wells at the exterior will be necessary. This complicates the whole business of providing EERO to the room because there are minimum sizes for the well that must be met. If it is over 44” deep it will need a ladder and it might even need some sort of guard to prevent someone falling into the well.

All of a sudden meeting the escape and rescue requirement has gotten even more expensive.

So let’s assume that you know there has to be proper EERO and lets also assume that you know there has to be a proper window well at the exterior too. In the following picture you can see that someone went to a LOT of work to build a very nice window well for EERO that is actually big enough for two adjacent basement rooms.

Window well

Window well

There is only one rather costly problem.

It is the wrong distance between the house wall and the outside wall of the well–only 28.”  That minimum dimension is 36.”

So while they had the “idea” right, they obviously did not know all the specific requirements that would prevent them from having to tear it all out and start over. It is also an indication of work being done without permits.

Whoops!

By Charles Buell, Real Estate Inspections in Seattle

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Hopefully, back in the day, we all got to fog up some windows!

I have blogged about this “defect” several other times, but I always find it interesting nonetheless.

Most of my readers, who have teenagers, can relate to the worry associated with them fogging up the windows on Lovers Lane on date night–when they were supposed to be home!

But lets ignore the teenagers for just a moment.

If you have garages, with overhead doors and automatic openers newer than 1982, you may know about the sensor beams/eyes located near the floor at both sides of the door.  These sensors are designed to reverse the door when a child, cat, dog or giant squirrel walks through the beam.

Surprisingly, I find this defect as many as 2 to 3 times a year.

Teenagers can be problematic more than 2 to 3 times a year.

These sensor beams are one of several reversing mechanisms required on modern automatic door openers and something your home inspector should be testing for proper function during the inspection.

It is a well know fact that teenagers apparently have no such reversing mechanisms.

One can only imagine the liability involved by installing the sensors other than where they belong–between 4” and 6” above the floor.

It is perhaps as dangerous as the teenagers in the back seat of the car—with their eyes stuck together.

 

Charles Buell, Real Estate Inspections in Seattle

Vented Crawl Spaces in the Northwest

I wish vented crawl spaces would just go away.

Wood Decay/Fungal Rot

Wood Decay/Fungal Rot

We could then turn the entire conversation into a discussion about conditioned crawl spaces. It is still the norm to have vented crawl spaces in the Northwest.  New vented crawl spaces are being built every day, in numbers much greater than conditioned ones.

It is important to understand how crawl spaces work because we are going to continue seeing them in older construction, as well as in newer construction.

If you live, or have lived, in other parts of the country, some of this may seem counter intuitive.  One could create problems in the crawl spaces of Minnesota or Georgia if one did some of the things we have to do in the Northwest. 

The numbers one puts in the equations are different, but the science is the same.

Getting just a few things right will allow a crawl space to behave itself and manage moisture conditions adequately.

The crawl space should be constructed such that vents can be installed on at least 3 sides.  A good vapor retarder on the crawl space floor is essential to the success of most crawl spaces. 

It would be nice if all the seams of the plastic were welded together and all the edges were caulked/sealed to the foundation.  However this degree of tightness is not necessary.  I have seen crawl spaces with floating vapor barriers and normal wood moisture content levels.  Adequate passive ventilation will remove the amount of vapor that finds its way around the seams of the vapor retarder. The building codes dictate how much ventilation is to be installed around the perimeter of the crawl space.

Crawl spaces that only allow for the installation of vents on one side, or two sides, may require a means of moving air through areas of poor circulation.  This can be accomplished with vents at the open side that are ducted to the poorly vented areas.  We then install a power vent fan in the duct to move the air mechanically.

Power vent

Crawl Space Power Vent

It is unusual to see crawl spaces that need mechanical ventilation. It may be warranted in instances where enough passive ventilation cannot be installed. You certainly cannot fix a moisture issue in a normally vented crawl space with power ventilation.  You first  must address the moisture issue.

The purpose of crawl space vents is not to lower moisture levels created by flooding and plumbing leaks. 

The purpose of venting is to deal with minor amounts of soil moisture vapor and to lower humidity that builds up seasonally.

We must understand the science of Northwest crawl space moisture.

On a recent inspection there was a power vent installed.  Operation of the fan was based on crawl space temperature.  It was set to run at 50°F.  It was running at the time of inspection. The unit’s built-in sensor shuts the unit off at 40°F.  This particular system operated under the assumption that the higher the temperature, the more the fan needed to run. 

This is exactly opposite the science.

In the summer we have moderate relative humidity and higher temperature than we do in winter.  In winter, we have very high humidity with lower temperature. 

70°F at 65% humidity would be normal in summer, while 37°F at 80% humidity would be normal in winter. 

While humidity in summer is lower than in winter, the “actual amount” of moisture in the air is much higher in summer.  Warm air can contain more moisture.

In summer, when that warm moist air enters the crawl space, it mixes with the warm wet crawl space air to effectively raise humidity levels in the space as it passes through.  This elevated humidity in turn raises wood moisture content of the crawl space framing.

In winter, the air outside the crawl space has very high humidity but at low temperature.  When we bring that wet cold air into the crawl space, it mixes with the warm moist crawl space air and effectively lowers the humidity as the air passes out of the space. Wood moisture content of the crawl space framing lowers as humidity drops.

Crawl space wood moisture content goes up and down with the seasons.

If we do not recognize this, plan for it and build for it–bad things are likely to happen. A few of those “bad things” might be mold, rot and wood destroying insects.

ANOBIID BEETLES:

When we do not control moisture levels in the crawl space, it becomes vulnerable to wood boring Anobiid Beetles. 

This is true even if there are no other uncontrolled moisture sources.  Anobiid Beetles prefer wood moisture content between 13% and 18% so it is important to keep wood moisture content below 13% in the summer.  A properly vented crawl space can do that.

When I find moisture levels around 13% in summer, I generally do not worry about it as much because I know moisture levels will drop below that in winter.

If I find moisture levels at 13% in winter, it is more of a concern because wood moisture content will be higher in  summer.  This is when the crawl space is vulnerable to infestation by Anobiid Beetles.  Moisture levels must be brought under control.

Anobiid Beetle exit holes

Some climates that are dry in the winter close their crawl space vents in the winter. Closing vents in winter in the Northwest would result in increasing moisture levels in the space year round.  

Wood moisture content will increase if the power vent is allowed to run all summer.  In the winter, when it is colder, the fan will shut down.  We will not lower the levels that built up in summer–levels that increased more than normal because of the fan. If you have a situation where power venting is necessary, the fan should run in winter and not in summer. 

A good vapor retarder on the crawl space floor and repairs to all bulk water issues is assumed.

There are vendors in the Northwest that would have consumers believe that no crawl space can be successfully vented.  This likely has more to support product sales than science.

Charles Buell, Real Estate Inspections in Seattle and the Great Northwest