Spray Foam Kiln Insulation

[Tom the Sawyer]

Building my DH kiln has been a long time project - on the back burner to other things but, I have been trying to get it done.  Anyway, I had decided to use closed-cell, spray foam, to insulate the kiln chamber.  I figured that with the insulation properties, and the vapor barrier properties, it would be the best option, although it was somewhat more expensive.   

I called a couple of companies, including one recommended by a client, and ended up choosing them.  My kiln is framed with 2x4 walls and a 2x6 ceiling.  I installed 2" rigid foam in the ceiling and requested 3" of closed-cell, polyurethane, foam insulation in the cavities and at least 1" over the studs (to maintain the vapor barrier).  I was told that my project was a bit below their minimum but that they would probably just fill the cavities a bit more to make up the difference.   

The first day, they showed up, masked off everything, and got about 20 square feet sprayed.  They were having problems with the gun, disassembled it a couple of times, and finally gave up.  Came back a couple of days later, explaining that they had started using a new formulation and, apparently, they had the temperature turned up too high, so the foam was setting up in the hose.  Although they had supposedly got everything tuned up, nothing got sprayed the second day.   

Two weeks later they showed up, explaining that their gun wouldn't shoot the new formula so they had returned to the old formula, and finished (sort of) the job.  What a mess; there were clumps of foam as large as basketballs hanging from the walls, and other areas where I could see the studs through gaps in the foam.  They then used a small canister with an extension to fill the gaps.  I complained about the big chunks on the wall and they "cleaned it up" by sawing the chunks off using a reciprocating saw with a long blade that looked like a bread knife.  They took out at least 6 big, black, trash bags full of foam chunks.

I called the owner of the company and asked him to come take a look, he said, "we'll make you happy."  But then he had to detour to Florida for family affected by the hurricane (certainly justified).  Several weeks later he came out and didn't seem to be surprised.  He said, "oh yea, sometimes it looks like a moonscape." Everywhere you brush against an area where the shaved the wall, there is a cascade of foam dust. 

So, for those who have an opinion, am I being too picky, or does this look 'normal'?
 

 
 

 
 

 
 

 
 

 

[WLC]

 I don't have any experience with spray foam insulation other than what I have seen on those HGTV shows. But that looks to me like whoever was doing the spraying didn't have much experience.  There's a lot of waste there and waste is money out of their pocket. 

[xlogger]

Tom where you planning on boarding the inside to protect the foam?

[Crusarius]

Looks to me like they tried to spray to thick in one pass. That should have been two or three passes. Most companies only fill 1-2" in the cavities between studs. This is a very different situation.

[nativewolf]

Not too picky, that's a mess and it's not going to be simple to clean it all up.   I agree with the other posters that the applicators wasted a lot of material.

[Savannahdan]

Looks like the guy doing the installation is a caver and wanted to make you a man-cave.  I agree with you and others that it just doesn't look right.   

[woodshax]

I used to own a spray foam company here in Texas....that is an ugly job ...probably the ugliest I have ever seen...when doing metal buildings we had to spray it on smooth so it looked pretty but this is a kiln so pretty does not matter.....since they completely encapsulated the 2x4s you got close to 4 inches all the way around and in some places a lot more  (we used between 3 and 4 inches for deep freezers...anything more than 3.5 is a waste of money).   The right spray temp is very important to mix the A and B side correctly.....you can't stick your finger into the foam right?  So anything over 2 inches of 2lb closed cell foam gives you a pretty complete thermal and vapor barrier and most closed cell foams are rated for a 5 minute ignition barrier but you have to spray on another layer of barrier (like thick paint) to give you a 30 minute rating.....that being said, spray foam is just plastic and plastic burns and melts.....I would skin with r-panel to keep it safe.

Also,  they can only spray closed cell in less than 2 inch thickness in one pass (and then wait) or it will catch fire as it is being sprayed....the reaction between A & B generated a lot of heat.

Also the spray bottle they used is likely not 2LB... but about 1LB (we used it to fill in small gaps in open cell applications)  unless is was fire rated...it will burn first.

Good idea though and it will retain heat like nothing you have ever seen....I have a 20 ft container we are going to spray with 3 Lb roofing foam (just 1.5 inches)

[Tom the Sawyer]

This kiln is an indoor kiln.  It has a flat roof, a few inches lower than the trusses in my barn.  It is a dehumidification kiln, Nyle L200M w/power vents.  It is designed to load from the end using a kiln cart.  The plan was to use closed-cell urethane foam for superior insulation and vapor barrier properties - at a higher up-front cost.  The hard shell of the foam, and using the cart, meant that there shouldn't be any banging of the walls with boards, so no interior sheathing.

My preferred fix would be for them to shave down the high spots (which leaves a very rough surface), and then to spray a thin coat over everything to smooth and seal it.  Frankly, I don't think they have the skills to do that.  The owner, who described it as an "appearance issue", suggested that they could shave down the high spots and that I could then spray it with something called Sherwin Williams Dryfall, to provide a finished surface.  The third option would be to shave it down to the studs and install sheathing, and paint (at significant additional expense in cost and labor).

[VictorH]

Hi Tom

I've been spraying foam for 17 years, mostly for roofing applications but I do some insulating as well.

As someone has said it looks to be a open cell and not a closed cell foam.  If you can poke it with your finger and dent it easily or collapse the foam then it is most likely open cell.  Obviously not what you wanted or hired them to do.

The other possibility is that it was sprayed off-ratio.  Spray foam should be sprayed at equal parts of A and B side.  Several things can cause off-ratio.

The foam dust you described can be either from off ratio spraying or the chemicals being heated too much in the system (creating a sugaring of the foam) and one or two others that are less likely.

If you can still load a full load with the foam the way it is then I would cover it with 2-3 coats of Acrylic Latex paint (spray it) or better yet Acrylic Roof coating.  This will give you a moisture barrier which you may not have with the foam (and do not have if it's open cell).

Not sure what you are paying for this but if you leave it the way it is and paint it, I would renegotiate the price.

[Tom the Sawyer]

Just for clarification, it is closed-cell foam, surface is very hard, you can't dent it with a fist.  The dust comes from where they cut off the big clumps.  They used a reciprocating saw that had a blade about 18" long that reminded me of a bread knife.  If you brush up against the cut surface, or rub it with your hand, it flakes off but he assured me that it was still a vapor barrier due to the closed cell. 

The worker who was having so much trouble spraying it said that, on the first day, the gun was plugging up and they had the gun rebuilt by a dealer's shop.  It happened again and he said that he didn't know that the formula had been changed and that he had set the temperature too high.  Apparently, their equipment couldn't handle the newer formula so they re-ordered the old formula in order to finish the job.  I can't say that I am that confident in their explanation.  The owner said that they often have large clumps like that on jobs, like the interiors of attics, where no one would see it, so no one cares.  I have clients who like to look around and I do care...  I've had clients look in to see how the kiln progress is going and they'll say, "whoa, did you do that?"  "No, I paid to have that done." 

[VictorH]

If he said that is what they get in attics then I would not be confident about their ability to trim and spray over smoother.  Once the initial cut areas have been swept over to remove the knife dust then those areas should not shed anymore.  If they can or do the foam is not to spec IMO.  They either have no clue as to what they are doing or are feeding you excuses.  I can completely rebuild a badly plugged gun (21 O-rings and seals) in a couple hours and field clean one up in 20 minutes.  I don't know of a single sprayer who does not maintain their own spray gun.  Oh and just to be clear there's not that much difference between manufacturers formulas with regard to temps and the ability of equipment handling things.

It's good that the foam is hard and you are confident it's closed cell.  Try painting an area and see if that improves its aesthetic.

[YellowHammer]

I don't think you are being too picky on the foam job. I have no experience with foam, but a kiln is a time consuming and expensive project and you've put a lot of effort and pride into it.  If you aren't happy, they shouldn't be happy, either, and should try to make it right.

All the dust should be removed to protect the finned refrigeration coils in the kiln.  Also, don't want it getting on the heat strips. 

Maybe there's a better way to smooth it out, then spray it with something thick, maybe truck bedliner?

[Peter Drouin]

Looks bad to me, but what do I know, I make 2x4s. Was he the low bidder?

[woodshax]

I agree with everything Victor said.....but having them try to fix it will likely just make it worth.....seems like the foam came out pretty much on ratio and there are some foams that require a much bigger mixer and you have to mix for a long time before starting to spray......There is also the possibility that they got a bad batch of foam....every so often when Quad foam came out we would get a bad batch and it just would not do what we needed it to do.
Dryfall is just paint that dries quickly so when the particles float to the ground, it is dry and you can just sweep it up.   The saw they use is the industry standard but mostly used for open cell ....there are scrubbers....but the dust they create when chewing up the foam is ridiculous..... If the heat in there is not going to get hot enough to worry about melt/burn.... then cut down the really high spots and latex paint....If you want it pretty...just skin it with panel

[Tom the Sawyer]

Not the low bid, but much less than the highest bid I got, it was $1500 for 465 square feet - about 3.22 p/sq. ft..

[Peter Drouin]

For that much $$ I would have expected a better job too.

[scsmith42]

I've always used $2.00 per square foot as a budgetary number for closed cell, and $1.50 for open cell. 

[Tom the Sawyer]

Well, the $1500 was their minimum job.  For me, it worked out to 3.22 p/sqft, I don't remember what their square foot rate was, seems like 1.80 for 1" and .45 for each additional inch.

[Kbeitz]

I have been around that stuff. One problem I see is not enough room to work.
It's like painting a car. If you don't have room to swing the gun you will get over spray.
You need lots of room to get a nice flat look.

[Cazzhrdwd]

 

  

  I had mine done to one inch for the same reason, moisture barrier. I had to also complain because I could see the plywood underneath. They came out and put another inch on. Mine isn’t quite as messy but messy enough. If they did three inches I think It would have looked like yours. I’m pretty sure if I took the gun from their hands I could have done a smoother job.