Monday, August 24, 2015

Capillary Break

Capillary Break
So we are under construction!

The foundation has been dug, 
The footers have been formed
and poured.

Now we are ready to start laying the ICF blocks... Right

        If we get too far ahead of ourselves we will miss a fairly important step. The capillary break is installed between the footer and the foundation wall. Concrete has amazing capillary action potential. Remember in science class in 3rd grade when the teacher added food coloring to water and put celery into the glass and we all watched the water travel up the celery. That is capillary action. 

        Why is capillary action bad? When you waterproof the outside of your foundation, water that is wicked into your foundation wall needs a place to go. It can't go out (though the water proofing) It must go in (into your basement). I will be insulating my basement walls beyond the standard ICF's, so I need to keep the insulation dry. 

       How much water can really get into your house this way? Isn't this just more precautions than anything? Well - concrete is VERY GOOD at wicking moisture - so good in fact that if you had a building 6 miles high, water could wick to the top - that's right 6 miles

     What can be used as a capillary break? Really anything that will stop water - water proofing, plastic, foam, etc. There are actual "Capillary Break" materials sold at local lumber yards - HOWEVER, they rarely stock it since no one ever asks for it. 

      This left me in quite an interesting situation. We had a few options

1) Garage Floor sealer - it has a curing time of 20-30 days - Nope
2) 6 mil plastic - there is a lot of rebar coming though the footer that would need a lot of attention to detail with sealing all of the holes (110 holes to be exact)
3) Low Perm Paint - Pretty expensive, and unsure of long term performance
4) Basement exterior water proofing - the chemical's in the water proofing tend to eat foam (ICF's are about 90% foam) when they are not cured - the cure time was 24-48 hours

None of them were great options. but we decided to go with the basement exterior water proofing:

We snapped a few lines to identify the area's the concrete will be in contact with the footer, to minimize the contact between the ICF and Capillary Break. 

It looked a little like this when we were done:

While it is a simple step, and set us back a half day or so, it will go a long way to keeping our basement dry!

ICF installation coming up next!

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