Insulation for Woodshop

[Dick Sylvan]

I am upgrading a 65+ year old garage to be a more comfortable workshop and will sonn be adding insulation to the walls. Applegate Cellulose Insulation has been recommended for the walls by a local contractor. I live in Houston, so I am primarily insulating for the hot months though it can get very cold (and damp) during parts of the winter. I am not yet sure what I am going to do overhead because the roof may or may not need to be replaced. Anyone have any experience with cellulose wall insulation in general or Applegate in particular. Thanks. I am also about to do a cut out for a "window" style a/c unit. Any suggestions/warnings there? The exterior is pine siding.

[Jay Radke]

"very cold" is a relative term. it gets "very cold" in chicago too. it also gets "very cold" in the upper plains in canada. but all vary by quite a few degrees. more like what is "very cold" in huston might only be the high in chicago for the day.

[Dick Sylvan]

You are right that "very cold" is a relative term, but 25-30 degrees and high humidity here makes even some of the former Yankees among us complain. But the real issue is the very hot and humid summers which is also relative with Houston being on the high end of the relativity scale.

[Jim Becker]

I really don't like cellulose for any number of reasons. If the walls are open, closed cell spray foam will be the most effective, stiffen the structure and provide it's own vapor barrier. Otherwise, I'd use R-15 batts in 2x4 and R1`9 batts in 2x6 for walls, either with integral kraft vapor barriers or unfaced with a poly vapor barrier applied after installation. (I most often do the latter at this point.

[Dick Sylvan]

So why was this moved. Building a workshop is not part of "General Woodworking" ? I'm sure I will get lots of response in the "Off Topic" forum. BTW, I am referring to blow-in cellulose insulation, not batted insulation.

[Jim Becker]

Blown in insulation in side walls is sometimes an "iffy" proposition unless you can map every piece of blocking and other things...assuming the wall is closed. If it's open and you're referring to the type of cellulose that goes on like spray foam in open walls and "sticks", it will do its intended job. But do investigate the properties for the product and insure you are comfortable with them, particularly for long term.

[Dennis Peacock]

Hey Dick,

Will your shop walls be open during the "upgrading" phase of your shop improvements? This can make a difference on what is suggested for insulation and methods of getting the insulating work accomplished.

What I've done with open stud walls is to apply the paperbacked R-11 in 2x4 stud walls as well as the R-19 in 2x6 stud walls with very good success.

As to your A/C opening, just make sure that you have good support to mount the frame of the A/C unit to when installed and I also made sure I had a solid surface (like your siding) to add the exterior bracing for the unit once installed. Just take a stick and pack a little of the left over insulation around the inside of the A/C unit to better seal it off after you have it installed. Sure makes the shop nicer to be in during the hot-humid southern summer months. :D

[Jim Becker]

Dennis, R13/R15 is the current preferred fiberglass batt material instead of R11. Both fit into the same 2x4 stud bay as R11 and provide increased insulation performance. I'm actually surprised that R11 is even still on the market as it hasn't met code in most areas for a long time...

[Dennis Peacock]

This thread was moved back to the General Woodworking forum section by me.

Maybe others can post their recommendations for Dick on his shop remodel. :D

[richard poitras]

Dick, I work with Dow insulation material every day on a nation level the best insulation Is a closed cell spray foam, but it comes at a hefty price, fiberglass insulation is not very good and is on the low end of the insulation scale do to the fact air goes right though it and do to the age of your building (65+ year old garage) you would loose a lot of insulation value from air loss, as a general rule of thumb you can loose up to 25% of your heat/cold in a building do to that fact. A blown in cellulose insulation will stop more of the air loss and have a higher r-value per inch than regular fiberglass so I guess its up to you and your budget as fare as what direction to go in …good luck

[Bryan Berguson]

I've used soft foam (open cell) and hard foam closed cell insulation in my house and garage. (also blown in cellulose and cotton bats but I won't go there... ) My house walls are done completely with soft foam and part of my garage is done with hard foam.

If I were building over, hard foam would get the nod for everything. I can't quote figures on R value other than it is higher than soft. And, I'll second what Jim (I think) said about it making your building stronger. The foam is quite rigid and does a good job of making a solid wall.

I believe when I got it done(about 5 years ago) it cost .75 for the first inch and .50 for each additional inch per sq foot. A good installer can control the thickness and give you a super insulated building.

Bryan

[Jim Dunn]

I believe when I got it done(about 5 years ago) it cost .75 for the first inch and .50 for each additional inch per sq foot. A good installer can control the thickness and give you a super insulated building.
Bryan

Bryan are you suggesting that the small 12'X14' garden shed would cost, based on 31/2" walls $2600 to insulate:eek::eek:? That doesn't include the roof in figuring the cost.:confused:

If I added the roof square footage I'd be really over budget on this "garden-shed/play-house".:o

[Randy Denby]

One note...make sure the window unit is slanted a little towards the back to enable good condensate drainage. I would make the opening a little oversize for future replacement....just in case, so the next unit you buy will fit. Window units, nowadays, are notorious for their short lifespan..... in my observations and scuttlebut at the HVAC wholesalers.I would price a mini-split heat pump if you can fit it into the budget. Most of these have better quality compressor, electrics, copper, and energy efficiency ,etc.

[Jude Kingery]

I did what Jim has suggested to you, simply R15 fiberglass batt between studs, also in the attic, then dry-walled, taped and bedded the walls, just decked the attic for added storage space. Makes for a fairly nice temperature control until it hits about 95+ here. But our humidity is low here normally (wasn't this summer, usually is). I don't mind arid heat, but I do mind the cold and the shop stays fairly cozy in winter with just a little shop heater. I did that myself about 10 years ago and so far, so good. Best wishes! Jude

[Bryan Berguson]

Bryan are you suggesting that the small 12'X14' garden shed would cost, based on 31/2" walls $2600 to insulate:eek::eek:? That doesn't include the roof in figuring the cost.:confused:

If I added the roof square footage I'd be really over budget on this "garden-shed/play-house".:o


With hard foam you wouldn't need to fill the entire cavity. Probably 2 inches would be enough. Assuming an 8 foot wall I come up with 416 sq ft of wall space to insulate for a 12x14 shed. At 1.25 per sq foot, that comes out to $520. It's early in the morning so my math could be a little off so somebody correct me if I'm wrong. :rolleyes:

Bryan

[Jim Dunn]

It's early in the morning so my math could be a little off so somebody correct me if I'm wrong. :rolleyes:
Bryan

No Bryan, you think better in the morning than I do in the evening. I was figuring-----well never mind it was to much:D. Thanks for setting me straight.

[Maurice Ungaro]

I too, used foam (open cell) in the walls and ceiling of my garage/shop. It cost me about $1000 for a company to spray it in for me. Jim B. is right - this stuff acts like a glue, and stiffens up the framing members. A nice thing in hurricane areas. I left the insulation exposed on the rafters, as It doesn't bother me at all.

A real nice plus about the foam is that you get about an R-35 factor with it, and it dampens noise extremely well.

[Rob Diz]

I went a slightly different route when I insulated my garages shop. I had cinderblock walls on 2 sides and a garage door on a third. Ironically, the only wall with insulation was the interior wall I built when the shop when up.

I ended up gluing 1 x2s to the cinterblock using construction adhesives, and then stapled on a foil foam foil product I found. The outside is white, so it was also like painting. I was told that with the furring strips, I would get about an R 8 on the walls.

I also stapled two layers of the stuff on my garage door.

The project in total cost me less than $400, and my shop was brighter. Of course, I could still blow in some insulation on top when the next time (actually coming up) that I break into the garage roof (for new kitchen fan ducting). I think the stuff was called low-e foil foam foil products. as in www.low-e.com

[Bart Leetch]

Cellulose insulation

I am a little more out spoken about cellulose insulation.

I used to install insulation professionally. We used to vacuum out cellulose because it loses its fire retardant ability after a few years. I literally lights off like a torch. Several times we had cellulose vender's come to try & sell us on cellulose insulation & we always showed them our test of aged cellulose insulation by taking some 5 years old & older out of the vacuum truck hopper & dropping a match on it whoosh it was gone their embarrassed look & answer I guess I don't have much to sell do I was all we ever heard.

If you value your life, home, or shop stay away from cellulose.

The only proof of fire retardant abilities of cellulose is being able to take 5 - 25 years old cellulose out of a building & try & light it. No manufacture or insulation contractor has provided this proof to me yet.

I won't accept any other proof & you shouldn't either.

Talk & words of assurance are cheap your life & home & shop are not.

I have had insulation contractors on other forums E-mail me & tell me of their similar experiences. One told me he would only install cellulose if the person wanting it would sign a release that would absolve the contractor of all responsibility if there was a fire.

1. Rock wool = spun copper slag

2. Fiberglass = fiberglass

3. Closed cell foam = cool stuff. I'm still not to sure about this product when there is a fire. What chemicals does it put out in the smoke of a fire? Will the occupants be able to escape or be killed or incapacitated by the chemicals in the smoke?

[Jeff Wright]

I have yet to insulate my mini-split conditioned workshop, but my research is leading me to using closed cell rigid foam in the ceiling between the rafters. I have been cautioned NOT to simply staple batts of insulation up between the rafters as I have no way to ventilate that area and it would lead to rotting the wood and possibly premature failure of my new tile roofing system. There is no ridge vent and I am not about to cut out newly installed tile. My plan is to close up the soffits to the garage and lay the 2" (EXPENSIVE) closed cell foam in between the rafters right up against the roof system (I'm told that is fine). Then, with my shop environment conditioned using the the highly efficient mini-split system, all should go well. I am not going to bother insulating the block walls. The garage door is well insulated and newly installed (Florida's highest rated hurricane door . . . so sturdy that I use the door's horizontal 7" deep metal braces as shelving in the shop!). For a recent discussion on mini-split systems try

http://www.sawmillcreek.org/showthread.php?p=652710&highlight=mini-split#post652710

[Greg Crawford]

Dick,

I'm also in the Houston area, and I'm just adding fiberglass as I can. I have about 1/3 of my total wall space at R13, and about 95% of my ceiling. The stud/joist spacing is all haphazard, which makes the batts hard to install.

One of my main considerations is air leakage. If you don't have a good air/vapor barrier, the warm, humid air will leak in and hamper the effectiveness of the AC. Seal things tightly and install controlled ventilation, preferably with a system that can condition the incoming air, and it will help a great deal. Overhead doors are also very leaky, and can be tightened by adjusting the rails so the door gets better contact with the framing when closed. Another source of leakage in my shop is the area at the top of the walls where the exterior siding stops. Roofing felt (tar paper) was nailed on before the siding, but not mailed all the way to the top, so air can pass directly from the wall cavities to the attic. The foam would probably be least effected by this type of leakage, but with fiberglass, the "dead air" space is no longer dead with a flow of air through it.

Don't discount the walls with the sunny exposure, either. My big door faces West, and when the sun hits that, my shop heats up, period. I can't do much more on insulating the door, so I'm going to try hanging a roll-up shade in front of it and hope the neighborhood nazis don't pitch a fit.

Good luck,

Greg

[Dick Sylvan]

Thanks to everyone for your help. I'll let you know what I end up doing.