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SprayFoamSupply.com Posted: Jan 23, 2008 08:46 AM	Substrate conditions We went to start a job yesterday. 2x6 framing in the walls with OSB and 2x12 framing in the roof with plywood. It was 10 degrees outside with a 15-20 degree substrate temp. Got the kero heater out and fired up. Went around and checked the moisture content of the wood and it was 15-28%. I explained to the contractor that we needed under 18% to get proper adhesion of the foam to the substrate. Instead of being disappointed, he was pleased that we checked and didn't just spray anyway. We pulled off of the job without spraying. It was a bummer, but foam has to be done right. I hope that all of you newbies are checking the site conditions and are not spraying if things aren't 100%. George
Michael Flander Posted: Jan 23, 2008 05:29 PM	Many readers of this forum never post George, so I will ask the obvious question: What steps would you recommend they take at this point to reduce the moisture to a level you can spray at?
quentin Posted: Jan 23, 2008 07:02 PM	I would also ask what are some good products for measuring the moisture levels.
SprayFoamSupply.com Posted: Jan 23, 2008 07:14 PM	When we had our 200k kerosene heater going, you could feel the humidity in the air. The contractor thought that the heater was putting moisture into the building. I have heard that propane heaters give off moisture, but wasn't sure about kero. I wanted to know, so I left my heater going and opened a couple of windows on opposite sides of the house to let some air circulate. I took my moisture meter and checked a couple of dozen places around the room marking the moisture content with a marker. I left the jobsite about 11 am. I went back at 5pm to check progress. It was 85 degrees in the house and so humid. When I went around and checked the moisture content in the same places, it had dried out significantly. Places that were 25% were down to 15%. If you pushed the moisture meter probes deeper into the wood, there was still high moisture content in the middle. I could have left the heater going all night and the surface of the wood would have been dry enough to get good adhesion of the foam by morning, but the contractor and I were concerned with the wood still being too wet in the middle and possibly shrinking as it dryed more. He is going to hook up a modine heater in the building and run it for a week to really get it dry. If he didn't have that, I would have left the kero torpedo going until I got below 15% moisture in the center of the wood. Quentin, I use a 4 pin moisture meter to check moisture content in the wood. George
Michael Flander Posted: Jan 25, 2008 03:28 PM	Great info George. Thanks.
Posted: Jan 26, 2008 07:06 AM	george,,indeed the open combustions heaters are a hugh sourse of moisture and moisture vapor..you can figure on a day or two "for the building to turnover" if you put heat to it at temps around 20 degrees or less,,,and when the hot meets cold condensation occurs,,so the substrate more than likely will be too wet to shoot...fans, dehumidifiers and the like will help assist the process... keep in mind that heat "travels to" cold so in effect this moist warm are is being driven into the moisture permiable wood substrate,,,,hence your readings as you probe deeper... consider an outside sourse of heat (maybe trailer mounted) with collapsable ducting,,,you are introduceing dry heat into the structure,,and now you just battle the possiblity of hot-meets-cold condenstation which is unlikely and easily remediated with the use of simple fans...rent the bugger to other contractors when you are not useing it(ding ding ding!!!) (remember the bibbs filterglass house without the vapor barrier that had 2 175k btu whites, 3 additional assorted size, but smaller, kero torpedos going in it in the dog days of winter so they could get the rockin and paintin done,,,remember the water running out of the wall and the owner freaking out...i do...he wanted cheap he got cheap...and the remediation wasnt :) )....foamed a bit of his office too!
SprayFoamSupply.com Posted: Jan 26, 2008 01:28 PM	Mark, The surface of the wood after 6 hours was dry and well above 60 degrees. There is no cold surface for condensation to occur. I do not believe that there was any warm moist air being forced into the wood. Pushing the probe in deeper was measuring moisture in the wood that hadn't had a chance to come out yet. The contractor was having issues getting his modine hooked up, so I left him my kero unit to run all weekend. We will see Monday morning when I show up to spray and I will post an update. Geo
Tim O'Keefe Posted: Jan 26, 2008 06:30 PM	I find that when you first start a heater in an uninsulated room you will likely see condensation occur on the plywood due to the warm air (regardless of moisture content) contacting the cold surface. Once the substrate rises in temperature the condensation quickly evaporates. The moisture in this case is superficial and does not penetrate into the substrate such that it would require extensive drying times like George is referring to. At $5 and hour that is an expensive way to heat a house for the weekend. I certainly agree that the downside to spraying in less than optimal conditions can be catastrophic however! Tim Granite State Spray Foam Co.
Luke Kujacznski Posted: Jan 26, 2008 06:56 PM	Guys you are making this way to hard on yourselves. Yes the house needs to be heated, yes the substrate needs to be dry, why is that our problem? When the painters come to paint the don't have to heat the house to help the mud from the drywall to finish drying or the roofer have to finish putting the decking on the roof. WE put in all our contracts that it is the owners/builder/contractors responsibility to have the house readdy for us to spray. There is way to much liability involved with putting one of your heaters in a structure and letting it run over the weekend. I have been on two seperate jobs where a torpedo heater was the cause for the whole house to burn down, it was the drywallers and he had set it up correctly, but after he left somebody had to carry something through and the moved to a less then ideal location and forgot about it, 10,000 sq ft gone in 30 minutes, who got sued, the drywaller because it was his equipment. If a house needs to dry as most do when spraying in the winter make sure that the contractor sets it up and oversees it use. This we help you stay in business and most of the time the contractor will thank you for doing it right and being safe about it. keep the trigger pulled and keep your respirator on
SprayFoamSupply.com Posted: Feb 05, 2008 10:34 PM	Just wanted to follow up with anyone reading the thread. With the kero heater running for about 6 days, the frame was down to under 12% moisture content everywhere. We got the job done of course. George

Author

Comments

SprayFoamSupply.com

Posted: Jan 23, 2008 08:46 AM

Substrate conditions

We went to start a job yesterday. 2x6 framing in the walls with OSB and 2x12 framing in the roof with plywood. It was 10 degrees outside with a 15-20 degree substrate temp. Got the kero heater out and fired up. Went around and checked the moisture content of the wood and it was 15-28%. I explained to the contractor that we needed under 18% to get proper adhesion of the foam to the substrate. Instead of being disappointed, he was pleased that we checked and didn't just spray anyway. We pulled off of the job without spraying. It was a bummer, but foam has to be done right. I hope that all of you newbies are checking the site conditions and are not spraying if things aren't 100%.

George

Michael Flander

Posted: Jan 23, 2008 05:29 PM

Many readers of this forum never post George, so I will ask the obvious question:

What steps would you recommend they take at this point to reduce the moisture to a level you can spray at?

quentin

Posted: Jan 23, 2008 07:02 PM

I would also ask what are some good products for measuring the moisture levels.

SprayFoamSupply.com

Posted: Jan 23, 2008 07:14 PM

When we had our 200k kerosene heater going, you could feel the humidity in the air. The contractor thought that the heater was putting moisture into the building. I have heard that propane heaters give off moisture, but wasn't sure about kero. I wanted to know, so I left my heater going and opened a couple of windows on opposite sides of the house to let some air circulate. I took my moisture meter and checked a couple of dozen places around the room marking the moisture content with a marker. I left the jobsite about 11 am. I went back at 5pm to check progress. It was 85 degrees in the house and so humid. When I went around and checked the moisture content in the same places, it had dried out significantly. Places that were 25% were down to 15%. If you pushed the moisture meter probes deeper into the wood, there was still high moisture content in the middle. I could have left the heater going all night and the surface of the wood would have been dry enough to get good adhesion of the foam by morning, but the contractor and I were concerned with the wood still being too wet in the middle and possibly shrinking as it dryed more. He is going to hook up a modine heater in the building and run it for a week to really get it dry. If he didn't have that, I would have left the kero torpedo going until I got below 15% moisture in the center of the wood. Quentin, I use a 4 pin moisture meter to check moisture content in the wood.

George

Michael Flander

Posted: Jan 25, 2008 03:28 PM

Great info George. Thanks.

Posted: Jan 26, 2008 07:06 AM

george,,indeed the open combustions heaters are a hugh sourse of moisture and moisture vapor..you can figure on a day or two "for the building to turnover" if you put heat to it at temps around 20 degrees or less,,,and when the hot meets cold condensation occurs,,so the substrate more than likely will be too wet to shoot...fans, dehumidifiers and the like will help assist the process...
keep in mind that heat "travels to" cold so in effect this moist warm are is being driven into the moisture permiable wood substrate,,,,hence your readings as you probe deeper...
consider an outside sourse of heat (maybe trailer mounted) with collapsable ducting,,,you are introduceing dry heat into the structure,,and now you just battle the possiblity of hot-meets-cold condenstation which is unlikely and easily remediated with the use of simple fans...rent the bugger to other contractors when you are not useing it(ding ding ding!!!)
(remember the bibbs filterglass house without the vapor barrier that had 2 175k btu whites, 3 additional assorted size, but smaller, kero torpedos going in it in the dog days of winter so they could get the rockin and paintin done,,,remember the water running out of the wall and the owner freaking out...i do...he wanted cheap he got cheap...and the remediation wasnt :) )....foamed a bit of his office too!

SprayFoamSupply.com

Posted: Jan 26, 2008 01:28 PM

Mark,

The surface of the wood after 6 hours was dry and well above 60 degrees. There is no cold surface for condensation to occur. I do not believe that there was any warm moist air being forced into the wood. Pushing the probe in deeper was measuring moisture in the wood that hadn't had a chance to come out yet. The contractor was having issues getting his modine hooked up, so I left him my kero unit to run all weekend. We will see Monday morning when I show up to spray and I will post an update.

Geo

Tim O'Keefe

Posted: Jan 26, 2008 06:30 PM

I find that when you first start a heater in an uninsulated room you will likely see condensation occur on the plywood due to the warm air (regardless of moisture content) contacting the cold surface. Once the substrate rises in temperature the condensation quickly evaporates. The moisture in this case is superficial and does not penetrate into the substrate such that it would require extensive drying times like George is referring to. At $5 and hour that is an expensive way to heat a house for the weekend. I certainly agree that the downside to spraying in less than optimal conditions can be catastrophic however!

Tim
Granite State Spray Foam Co.

Luke Kujacznski

Posted: Jan 26, 2008 06:56 PM

Guys you are making this way to hard on yourselves. Yes the house needs to be heated, yes the substrate needs to be dry, why is that our problem? When the painters come to paint the don't have to heat the house to help the mud from the drywall to finish drying or the roofer have to finish putting the decking on the roof. WE put in all our contracts that it is the owners/builder/contractors responsibility to have the house readdy for us to spray. There is way to much liability involved with putting one of your heaters in a structure and letting it run over the weekend. I have been on two seperate jobs where a torpedo heater was the cause for the whole house to burn down, it was the drywallers and he had set it up correctly, but after he left somebody had to carry something through and the moved to a less then ideal location and forgot about it, 10,000 sq ft gone in 30 minutes, who got sued, the drywaller because it was his equipment. If a house needs to dry as most do when spraying in the winter make sure that the contractor sets it up and oversees it use. This we help you stay in business and most of the time the contractor will thank you for doing it right and being safe about it.

keep the trigger pulled and keep your respirator on

SprayFoamSupply.com

Posted: Feb 05, 2008 10:34 PM

Just wanted to follow up with anyone reading the thread. With the kero heater running for about 6 days, the frame was down to under 12% moisture content everywhere. We got the job done of course.

George

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