Jan 30 10 Inspection #18
My last inspection of the month took me to the Bancroft area this would represent number 18 for the month. For anyone that is counting the posts you will notice that the documenting of every single inspection has not happened. The reason for this can be summed up in one word BORING very often it is simply going through the motions. Yes this is good news for the home buying public. A boring inspection for me is a good inspection for the buyers in most cases. Occasionally I will come across a home that is very interesting either due to architecture or just the quality of work. It is a good job to have when you can go into the home and your explanations are about superior workmanship or clever ingenuity. Everyone walks away feeling good.
My Bancroft inspection was interesting, but not for any of the above reasons. It was interesting for the reason that, thanks to Mother Nature I was able to visualize one of the many theories that I speak about when trying to explain what has caused the defects that I have found. In this case it was in a crawlspace (Remember in the past postings I mentioned where the bulk of the sins are found) The situation that I found was a convection current of air within the cavity of hollow masonry foundation wall, and how as warm air rises up through the hollow cavity it picks up moisture that is laying in a liquid form with in the this space. Due to improper surface drainage the ground has been saturated to the point where it has placed a hydrostatic pressure against the foundation thereby causing water to penetrate the mass of the block.
As this warm moist air rises up the cavity of the block foundation, it reaches the top and comes into contact with the bottom of the wood sill plate, rim joist and floor joist where the warm air condenses, (due to the below freezing temp.) turns to moisture and forms frost. This is where Mother Nature came in. The day of the inspection it was -15 c outside and colder inside( no heat in the building ) due to this I was able to see a complete frost line of how the moisture laden air was moving as it left a perfect imprint on the framing that it came into contact with it. This condition, left unaddressed quickly leads to significant structural problems, mould and wood rot.
The good news is that at this stage the problem was easily addressed. Correcting the cause of the problem is the first step. Eaves trough clean and in good working order, down spouts that extend a minimum of 4 feet from the building and finally ensuring that the grade is such that the water runs away from the building. Once this is done the next step is to seal the top course of block to eliminate the convection current of air within the bock cavity. This can be done with spray foam insulation or with masonry.
Crawl spaces can have a wide array of concerns, you can be sure that we will talk about them again in the very near future.
Thanks for tagging along