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Spray foam - applying to cold steel during winter


RAP

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Hello,

 

Is it a good idea to have spray foam insulation applied to cold steel or should this be left until the weather is warmer?

 

I have a quote from Websters, job provisionally booked in for December, where they state that the steel surface must be dry and to ensure that sufficient dry heat can be provided (no gas heaters) to heat the boat in order to prevent condensation forming on the surface. Keeping the boat well ventilated while heating will help considerably.

 

This suggests that I would need to hire a reasonably decent electric heater/blower. Obviously, I am not an expert and spray foaming is a first for me, but I would be interested to hear from those who have experienced this and provide any useful advice.

 

Many thanks, I appreciate the help.

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Hello,

 

Is it a good idea to have spray foam insulation applied to cold steel or should this be left until the weather is warmer?

 

I have a quote from Websters, job provisionally booked in for December, where they state that the steel surface must be dry and to ensure that sufficient dry heat can be provided (no gas heaters) to heat the boat in order to prevent condensation forming on the surface. Keeping the boat well ventilated while heating will help considerably.

 

This suggests that I would need to hire a reasonably decent electric heater/blower. Obviously, I am not an expert and spray foaming is a first for me, but I would be interested to hear from those who have experienced this and provide any useful advice.

 

Many thanks, I appreciate the help.

Do not even contemplate Spray Foam unless you can get the steel warm and dry.

 

A fan heater or four will help but otherwise I would wait until late April and even then would want some fan heaters on standby.

 

A wet or dry dock with heating would help.

N

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I thought a moist surface helped the foam to expand, cure and stick to the steel? I always lightly spray the surface with water if I'm using cans. Is hand held PU foam chemically different to that applied by professionals? (See instruction no. 4 in the link below)

 

http://www.polycell.co.uk/product/polycell-expanding-foam-polyfilla/

 

A warm surface & environment will also help the foam to expand properly, so perhaps a cold winter day isn't ideal.

Edited by blackrose
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I thought a moist surface helped the foam to expand, cure and stick to the steel? I always lightly spray the surface with water if I'm using cans. Is hand held PU foam chemically different to that applied by professionals? (See instruction no. 4 in the link below)

 

http://www.polycell.co.uk/product/polycell-expanding-foam-polyfilla/

 

A warm surface & environment will also help the foam to expand properly, so perhaps a cold winter day isn't ideal.

The stuff websters use is a two pack, mixed at and by the spray gun. It comes out as a liquid and starts to expand after the liquid has wet the steel. I therefore guess it is a different sott of PU to that in cans.

 

I know someone who had spray foam onto a patchily damp but otherwise clean steel surface and it did not adhere properly in lots of places. Beware too of the condensation from breathing as you set up for the spray job on the day.

 

N

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I DIY'd a "two pack" sprayfoam a couple of years ago, and although I can't comment on whether moisture is a problem, low temperatures certainly are. If it isn't warm enough, the foam doesn't expand as expected.

 

I can't remember exactly how warm the steel should be, but I applied it in September, and only just got away with it - in fact the coverage was well below what I'd calculated, probably because of low expansion: I ended up having to add Kingspan over the top. So, don't skimp on the heating, I'd say!

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I ve just finished fitting "Celotex" foil backed insulation to my sailaway. Taped all the joints and nearly

finished stapling Tyvek "Airguard Reflective" Total cost just over £600 and two and a half days work on my

57foot sailaway. Both items are designed not only to insulate but more importantly to reduce/prevent

condensation caused by the warm interior air contacting the steel hull.

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Some great responses here, thanks. My boat is in the water and I expect keeping the steel below the waterline warm and dry will be impossible in December. I am surprised that Websters have not advised that this will be an issue. I will be postpone the job until warmer weather.

 

Jddevel, what did you use to stick the celotex to the steel?

 

Many thanks.

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Are Websters guaranteeing a certain thickness? If they are, lower expansion might not be much of an issue - I'd guess (though I don't know for sure), that the U value would be only slightly worse with the same thickness of denser foam - my problem was that I only had one foam kit. If you were to go ahead, I'd make really sure that Websters had clearly stated their exact requirements, and guaranteed the results (I've never used them, so this isn't a comment on them, just an abundance of caution!)

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Did not have to stick it cut it to exact size and pushed it in between the battens already fixed to the steel

to which the finished panels are to be fixed. Also in my case as I have then stapled the airguard to the same

battens the Celotex can`t fall out anyway. If I hadn`t used the airguard I would possible have used a cheap

net or twine again stapled to the battens to hold temporarily in place before fitting the final hull panelling.

in a couple of places i.e. around the water tank where there are no battens I used a suitable grab adhesive. if you pm me I`ll send you some pictures.

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