Membranes and Tapes on a Budget
I wanted to see is anyone had any feedback on membranes and tapes that do not break the bank?
The cost of say the Siga membranes is high but justified for the quality, however it is products like the nail sealing tapes, seam tapes, and flashing tapes that really add up. Some of these product systems cost nearly as much as decent CDX plywood per square foot once you factor in the accessories(tapes).
Currently I am building with typical double stud wall construction in Northern New Hampshire. I can get the Siga products locally so hoping to use them where needed. For example on the inside of the space there seems to be no cost effective options for vapor intelligent products other than the CertainTeed Membrain which looks to thin and flimsy in my opinion, so going with SIGA Majrex 200 here.
On the exterior walls and roof there seems to be plenty of more cost effective options that might not be as high of quality as a Siga or Pro Clima, but Tyvek and Typar for the walls and Felt Buster on the roof are all vapor permeable and much cheaper. The same goes with flashing and seam tapes. Zip tape is pretty robust stuff.
For my project we are not talking about a ton of $$$ here, but just swapping from say a SIGA Majvest 200 to a Tyvek and the Majcoat to Felt Buster would save my own home project nearly $2000.
For example the SIGA nail sealing tape for the entire roof is $800 where a commodity butyl sealing tape for roofs or deck joists is 75% less or more.
What are folks using to get a high performance envelope without breaking the bank?
Thanks!
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Replies
sb1616ne,
I agree and so I think does Martin: https://www.greenbuildingadvisor.com/article/are-expensive-building-components-necessary
The other side of that is making sure that the work needs doing at all. In the rarified world of very high performance houses, a lot of things are done which may further building science, but don't measurably improve the energy performance or comfort of the building. So for instance I don't see any justification in taping nail heads, or following advice to seal each stud bay if there is an effective air-barrier already in place. Pick your battles, and decide on priorities remembering you are trying to make a house to live in, not optimizing a machine.
I think you're on the right track in terms of trying to figure out what has reasonable alternatives and what doesn't.
- Certainteed Membrain feels too flimsy? Use the SIGA smart vapor retarder.
- Need a mechanically-fastened WRB? Tyvek Commercialwrap is probably going to be just fine, no need for the SIGA product.
- Tape for air sealing sheathing: does 3M All-weather Flashing Tape 8067 save any money over SIGA Wigluv? It was another one of the top performers on Martin's backyard tape test.
As far as air-sealing goes, the proof is in the blower-door test, so if you can hit the numbers you're targetting without going head-to-toe SIGA, great!
The other one to think about is how much does saving $1000 matter in terms of the overall project? In a million+ dollar house with all the bells and whistles, I'd be inclined to say don't waste the brain space on saving pennies and just use the SIGA stuff. But if this is a $450,000 house, and you really thought it was gonna be a $350,000 house before you got hit with covid-related cost craziness, then maybe pinching pennies is worth it!