Conditoning a crawl space: process and materials
I'm trying to find a contractor to do a job that I cannot do due to medical issues. But, what I can do is have specs in the proposal consistent with what I expect. I have read Martin Holladay's comprehensive article on how to condition a crawl space.
The contractor may be open to using battens to secure Tu-Tuff, but he is requesting an explanation for use of the battens. He prefers to run the Tu-Tuff (vapor barrier) only up 6 inches and seal edges against wall with a non drying mastic. Then follow with application of Thermax, also adhered to wall with mastic. Personally, I think that this may not be the optimum plan. Concrete walls seep moisture More on this below.
I, too, am not sure of the rationale for the battens. Is it for keeping the Tu-Tuff taut while using minimum amount of mastic? Is it for having a firm flat surface to later apply Thermax sheathing?
Are the battens to be placed horizontally to form a perimeter at the top of the wall?
RE: application of Tu-Tuff:
Is it overkill to run tu-tuff all the way up the walls since Thermax will also be applied? Or, is this for getting a more complete seal against moisture from the exterior walls?
As aside I heard what seems like a good tip when applying tu-tuff. The distributor (EFI) of tu-tuff recommended the following: caulk and staple tu-tuff to wooden sill; run down the walls, use a 2x4 to (temporarily) hold tu-tuff in place at the bottom of the wall (no battens), and then keep running the tu tuff barrier onto the crawl space flooring. Personally, I don't like covering any of the wood above the foundation, but I do like the tip on using a 2x4 to keep it snug and avoid accidentally tearing it. For attaching tu tuff to the wall: concrete screws and a solid bead of sealant (one that does not dry and has low voc)???? Any specific sealant to recommend?
RE: application of thermax:
Would it make sense to adhere thermax first and then cover with tu-tuff? Which goes on the wall first? Personally, I would opt for thermax to face the interior, not the wall. If so, how should the thermax be applied? Concrete screws?
RE: ezbreathe fan
Contractor suggested this as a way to supplement existing radon mitigation...which is a little outdated...done 28 yrs ago and current average reading over 92 hurs is 11 (4 is the standard). Evaluator did a sniff evaluation to locate source of leaking radon...coming mostly from crawl space. We like the idea of getting fresh air into the house, but I don't like it that this company does hard selling and totally lacks empirical supportive data. Contractor is offering this equipment and installation at cost....he itemized it to back up his claim. Any thoughts on this application. Forget it? Or, other similar products better...like honeywell...better?
But, the more that I ponder this product, the less I like it. Keep it simple and just cut a big enough hole- register in the existing duct work for forced air to come out. This creates some positive pressure which helps seal everything in the crawl space. Whereas, ezbreathe creates negative pressure. However, since I have a radon problem, it might be better to spider the pvc instead of just having a single stub.
Yes, I am guilty of being obsessive and not trusting a contractor. The prices that I have gotten are extremely high. I have secured prices for all the materials---a liberal estimation is 950.00. Yet, two contractors come in at 4k. Plus, both initially fail to use material up to code.
Posted Oct 31, 2012 1:06 PM ET
Edited Oct 31, 2012 1:12 PM ET
Other Questions in Green building techniques
New 20+ SEER Variable Carrier heat pump w/ Greenspeed Intelligence system creating moisture & performance problems in the crawl
Is it OK to step the slab thickness over the footings to accommodate insulation between the slab and the footings?