Workshop Insulation

[jadefox]

We're enclosing a section of our 150+ year old barn to be a workshop, and we're thinking through insulation. There are two exterior walls to the new workshop that are sheathed in horizontal boards and then sided with shingles. In places there is old (very) tar paper between the sheathing and the shingles. We plan to replace the shingles and may add a WRB at that point, but that won't until next summer at the earliest. We want to insulate now from the inside, and we have access to some reclaimed 4x8 sheets of 1-inch thick rigid yellow polyiso insulation. We plan to panel the interior of the shop with boards.

Thoughts on the installation of the polyiso or other insulation? The interior two walls will also need to be insulated, but those are new walls built between the beams.

Thanks in advance!

 

[bigtiller]

WRB :confused3:

 

[jadefox]

WRB :confused3:

Sorry. Water resistant barrier (e.g., Tyvek)

 

[Snobdds]

Well, Tyvek is for the outside, but yes I would not go without these days. It's more than just a water barrier. It's an air barrier.

You don't have any wall framing for traditional roll insulation. That leaves only rigid Styrofoam (which has a pretty low R value unless you really increase the thickness) or spray foam. The spray foam would be the best and you could forgo the Tyvek, but all that pretty barn wood would forever be damaged.

I would spray foam it and not worry about it.

 

[teejk]

We're enclosing a section of our 150+ year old barn to be a workshop, and we're thinking through insulation. There are two exterior walls to the new workshop that are sheathed in horizontal boards and then sided with shingles. In places there is old (very) tar paper between the sheathing and the shingles. We plan to replace the shingles and may add a WRB at that point, but that won't until next summer at the earliest. We want to insulate now from the inside, and we have access to some reclaimed 4x8 sheets of 1-inch thick rigid yellow polyiso insulation. We plan to panel the interior of the shop with boards.

Thoughts on the installation of the polyiso or other insulation? The interior two walls will also need to be insulated, but those are new walls built between the beams.

Thanks in advance!

If your horizontal exterior backer boards are in good shape and will remain as you update the exterior siding, I guess the trend would be to use sprayed foam...not cheap but the cost is coming down as more people are getting in the business. From what I have read heat loss from a side-wall is not that much if you can eliminate drafts/air infiltration and foam will do that. Biggest heat loss comes from your ceiling I think. There are a lot of people on this site that know a lot more about it than I do so stay tuned for more advice. Interior partition walls...my shop is partitioned between hot and cold with 2x6 framing. I used steel for the interior so my "nailers" run horizontally so as to secure the steel. I spaced the "nailers" 24" OC and used Kraft faced fiberglass on the heated side (readily available in that width). Back side I put up OSB.

 

[jadefox]

Well, Tyvek is for the outside, but yes I would not go without these days. It's more than just a water barrier. It's an air barrier.

You don't have any wall framing for traditional roll insulation. That leaves only rigid Styrofoam (which has a pretty low R value unless you really increase the thickness) or spray foam. The spray foam would be the best and you could forgo the Tyvek, but all that pretty barn wood would forever be damaged.

I would spray foam it and not worry about it.

Thanks. The VRB will likely be added (on the outside) when we re-shingle the barn next summer (hopefully). For now, I'm really thinking of going with the rigid, as I can get it cheap and double up. If I do that, I'm thinking I should use spacers to create an air gap between the sheathing and the insulation. Thoughts? I have not totally ruled out spray foam (we did that in the attached barn, and it's toasty!), but I'd like to do as little to the barn that compromises any of its historic integrity (we're suckers for that kind of thing).

 

[jadefox]

If your horizontal exterior backer boards are in good shape and will remain as you update the exterior siding, I guess the trend would be to use sprayed foam...not cheap but the cost is coming down as more people are getting in the business. From what I have read heat loss from a side-wall is not that much if you can eliminate drafts/air infiltration and foam will do that. Biggest heat loss comes from your ceiling I think. There are a lot of people on this site that know a lot more about it than I do so stay tuned for more advice.

We used spray foam in the attached barn, and it's awesome. We did ceilings and floor too. It's a pain to then go in and redo and plumbing/electrical though, which is really the only down side (besides the cost and ruining the historic integrity of the structure).

 

[TractorGuy]

It would pain me to cover that historic structure with anything. Much less something that couldn't be removed easily. I think I would put on an extra jacket and build a double drum wood heater to keep warm.

 

[jadefox]

It would pain me to cover that historic structure with anything. Much less something that couldn't be removed easily. I think I would put on an extra jacket and build a double drum wood heater to keep warm.

Insulation of some sort is going to be necessary. Our business has grown much more quickly than expected, and we need the space. At present, snow blows in during the winter, so we need to button up this section (it's about two-thirds of one side of the first floor). Having said that, we are committed to maintaining as much of the historic integrity of the structure as possible. That's one reason we were thinking that rigid foam may be the way to go. Today I ripped out walls that were built over the years (last 25 years, I'm guessing) and uncovered more beautiful beams. It is our goal to leave as many of these exposed as possible.

 

[teejk]

We used spray foam in the attached barn, and it's awesome. We did ceilings and floor too. It's a pain to then go in and redo and plumbing/electrical though, which is really the only down side (besides the cost and ruining the historic integrity of the structure).

Cutting through that foam for pipe/wiring upgrades might be a bit messy but certainly is easier than cutting through 150 year old lumber. Go find a cheap "oscillating multi-tool"...or find a cheap fillet knife! As for historic integrity, costs more but there are ways to preserve your wood from foam if you want to bother but IMHO you will most likely lose some of the benefits of foam in terms of energy efficiency (probably not much)...thinking...