HardieWrap as Alternative to Blueskin
bongo30
| Posted in General Questions on
We are installing Hardie siding, and just got a quote for Blueskin as our WRB. The cost to install Blueskin is 10 times more than to install Hardie Wrap.
Does anyone have any experience with Hardie Wrap? Shall we tape all the sheathing seams just to get more air sealing?
If it makes a difference, our wall construction is Hardie, rainscreen, rigid mineral wool, WRB and sheathing. We are not near the water and not in high-wind area, if that matters for Hardie Wrap v. Blueskin. Thank you.
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Hardie wrap appears to be 4x cheaper than Blueskin, so the remaining difference in price seems either because the installer thinks Blueskin will need a lot more labor, or they are marking up for a "premium" product.
It's probably a bit of both: since Hardie wrap is stapled up like Tyvek (so very fast to install), and Blueskin is a fully adhered product, like a giant sticker (so has to be more carefully put up and rolled out). But Blueskin is also a higher performance product than Hardie wrap (in terms of air sealing), so maybe there is also some "luxury" mark-up involved.
My own related anecdote: I'm not a contractor and had little prior building experience, but I DIY installed a Blueskin VP100 WRB on my home. At the time (1.5 years ago) the Blueskin was 5x cheaper (in material cost) than the premium airtight, vapor permeable WRB alternative (Prosocco) that had been initially proposed.
In very pricey California, I paid $2500 retail (no contractor discount) for enough Blueskin to cover my 1600sqft house. It took me (singlehandedly/unexperienced) at most 80 hours of labor, but probably less. Afterwards I learned that I installed it the hard way (horizontally) instead of the easier way (vertically). Knowing that I probably could have cut the time I spent in half.
A real (AKA skilled/experienced) construction crew of 2 who already knew things like that could have finished the installation in a couple of days.
VP100 was 4x the cost of Tyvek when I checked a couple years back. No doubt it requires more labor and care to install and roll the entire surface (pressure sensitive adhesive) versus a staple-up, non taped product. I'd consider the increase in cost as a % of your entire project and the importance of getting the air control layer right.
Just to put things in the perspective. 2,880 home, 2 stories. Blueskin (materials and labor) quoted as almost $30k.
$30k is nearly the price I was quoted for a liquid applied Prosocco WRB - in the most expensive construction market in the US - so I would balk at that price for the Blueskin, which is far less expensive in both labor and materials than Prosocco.
You said below that your contractor has already done air sealing from the inside. If you have used closed spray foam for interior sealing, the air flow inhibition of the Blueskin will be redundant, and the vapor permeability of the Blueskin will be negated with respect to drying through the wall cavity, since I think closed cell spray foam is a vapor barrier. Taping the sheathing seams only makes sense if you don't have much faith in your interior air barrier.
If the standard stapled home-wrap is only $3k, I'd go for that. You aren't going to get $27000 worth of comfort or savings from the Blueskin. Far better to put that $ into solar or a good heat pump.
Thank you! That makes sense. It’s just such a significant difference 30k v. 3k that I’m thinking it may not be worth it.
Bongo30 Bongo30,
If you want the WRB to act as an effective air-barrier, then a self-adhered one makes sense. That's usually on retrofits, not new construction where there are better choices for air-sealing.
If you decide to go with a regular house-wrap you don't need to confine yourself to Hardi-wrap. My own preference is Tyvek Commercial Wrap.
I can't think of many circumstances when it's worth detailing regular house-wrap as an air-barrier.
That's a good point. My case of using Blueskin was a retrofit (50% of original plywood/osb sheathing replaced). For a new build, seems like integrated sheathing/air-barrier systems like ZIP-R make more sense. I don't understand in what scenarios the very expensive liquid applied WRBs ever make sense for residential construction, although I'm happy to be educated on that matter.
Dan,
I agree. I don't know what shortcoming in other WRBs they are solving.
I've heard claims that they will last much longer, but I have doubts that that is worth the cost. Maybe if you are building a castle to last 200 years, but for most people those costs and timescales don't make sense.
When you are saying air sealing, does air sealing from the inside count? We specified air sealing on the inside, but the contractor is asking if sheathing has to be calked on the exterior. If we don’t use Blueskin, would you recommend maybe taping the sheathing seams on the exterior to get better air sealing?
> We specified air sealing on the inside, but the contractor is asking if sheathing has to be calked on the exterior.
This seems like something the contractor should either know, or should at least be able to provide you trade-off around cost/performance/comfort.
They shouldn't be asking you as the client whether they should caulk exterior seams. If your contractor isn't able to provide you with the information needed to make the decision, this is also the sort of trade-off a home energy consultant can help you navigate.
I hired a consultant for my project to help specifically with things like this. For example, they helped me realize that in my climate zone and project, exterior insulation wasn't worth the expense.
B30 B30,
There is no right answer to this. It's a matter of how much redundancy you want. A primary and secondary air-barrier can make up for shortcomings in the initial air sealing and possible future damage. Many projects do just fine with a well detailed and executed single one.
Thank you! I feel better now about downgrading to either Tyvek Commercial or Hardie Wrap.
B30, B30,
I use Tyvek Commercial mainly because it is so much harder to tear than regular Tyvek. Hardi-wrap maybe similarly robust. I haven't tried it.
If you want to have some redundancy at lower cost, tape the sheathing seams with 3M 8067. If Tyvek was quoted at $3k, this should cost strictly less than that. Fun story: I had my 8 and 10 year old kids do it with me on my house, and it was a great bonding experience.
I recently heard (I think on the B&S Beer show) that the Benjamin Obdyke peel and stick house wrap product is much easier to install than the others. It may be worth pricing the material, and concurrently finding that B&S Beer show (it was a recent one) and let your contractor listen to it. Supposedly you can pull it off and re-adhere it to avoid all the folds that come with the other stuff.