Poorly installed sprayfoam repair

[dandandan]

Hello,

 

I couldn't find an answer to this problem so hopefully not repeated elsewhere.

 

We have had the same damp boat for three years and I have decided to confront it, starting with the bedroom (furthest from the burner and so worst).

 

I have taken the bedroom panels off to look at the insulation and it is pretty awful. Sprayfoam of varying thickness all over, down to about 5mm in places, never more than 25mm. The gunnels have been missed entirely down the whole length, both sides. There are gaps where the wall and roof meet (the installer has clearly not got behind the batten here as is evident from rust staining on the foam below). In a few places the sprayfoam has become debonded from the steel especially where the roof meets the wall. In some places the sprayfoam seems to have become saturated and is discoloured (I thought it was closed cell?).

 

Couple of questions:

1) What should I use to insulate the gunnels? Sprayfoam in a can/kingspan cut and stuck down with marineflex and then gaps filled with sprayfoam/something else?

2) What is the best way to build up the insulation thickness where it is very thin?

3) Where water has saturated the spray foam should I remove damaged material and replace or will it dry out?

4) If I patch up parts with sprayfoam will it bond to exiting foam and create a water barrier or will I need to do this on top of the foam with another material?

5) Some of the battens were soaking wet around the screwheads, is there an easy way to prevent this? Countersink and insulate?

 

Thanks for answers to any of these questions and any other advice!

 

Dan

[WotEver]

Taking just one part of your post I would use Kingspan for the gunwales and (maybe thinner?) Kingspan over the thin bits of spray foam, assuming you're talking about large areas. Use tinned foam to seal all joints between new and old. Use the same stuff to seal in nooks and crannies that you can't get at with Kingspan. Use the same stuff to adhere sheets to thin spray foam.

 

Others may have differing views.

[Chewbacka]

If it is a bad as it sounds and sufficiently rough to prevent the insulating board lie flush then I would consider getting - say half at a time - the boat professionally spray foamed again assuming the new stuff will stick to the old.

If you do go that route you need to ensure they are supervised or at least the foam is checked for coverage/thickness before you let them go or pay them.

 

You could use the foam in cans, but the fire resistant stuff is worth the extra, and you are going to need a lot of cans, hence my suggestion above may be cost effective.

[system 4-50]

Have you got proper professionally-applied sprayfoam or a diy amateur job?

I don't think my sprayfoam gets "soaked", water just sits on it, though I haven't set out to fully test it.

Beware of trying to patch it with cans, it can take dozens of cans, though this can still be a cost-effective strategy.

You might have to take all the old stuff off if it is no good.

[cuthound]

A quick 'n dirty way to check that your sprayfoam contractor has applied it thick enough, is to drive a nail through the centre of a short length of wood, so that the protruding end is the same as the agreed sprayfoam thickness (say 50mm) and press it into the sprayfoam.

 

If the wood won't go level with the foam, then it isn't thick enough.

 

If you do it in the presence of the contractor he can't argue and can top up any thin bits.

[dandandan]

Have you got proper professionally-applied sprayfoam or a diy amateur job?

I don't think my sprayfoam gets "soaked", water just sits on it, though I haven't set out to fully test it.

Beware of trying to patch it with cans, it can take dozens of cans, though this can still be a cost-effective strategy.

You might have to take all the old stuff off if it is no good.

Yes, I have no idea who did it.

 

The areas of saturated foam are very localised spots. Still strange that closed cell foam can become saturated.

[Machpoint005]

Yes, I have no idea who did it.

 

The areas of saturated foam are very localised spots. Still strange that closed cell foam can become saturated.

 

Erm .. if they are saturated the cells ain't closed!

[Robbo]

If it's like this in one area it's more than likely like this in another area. I would check other areas. The question is do you want to do the whole boat again or just tackle bits at a time? Getting someone in to spray foam it again will cost, so may not be worth it unless you can do the whole boat. You can get the equipment to do it which may be worth while.

 

One thing I found is using spray foam in a can is that it doesn't like spraying up on a surface, but I've only tried it with the straw, perhaps from a distance with out the straw is one way to get good coverage from a can? Anyone tried ?

Edited January 10, 2017 by Robbo

[ditchcrawler]

A quick 'n dirty way to check that your sprayfoam contractor has applied it thick enough, is to drive a nail through the centre of a short length of wood, so that the protruding end is the same as the agreed sprayfoam thickness (say 50mm) and press it into the sprayfoam.

 

If the wood won't go level with the foam, then it isn't thick enough.

 

If you do it in the presence of the contractor he can't argue and can top up any thin bits.

That is what I did, he had to come from Wale to Suffolk to fix it. Luckily I spotted it before I started fitting out. Some places like a coat of paint never mind 25mm

[Murflynn]

If it's like this in one area it's more than likely like this in another area. I would check other areas. The question is do you want to do the whole boat again or just tackle bits at a time? Getting someone in to spray foam it again will cost, so may not be worth it unless you can do the whole boat. You can get the equipment to do it which may be worth while.

 

One thing I found is using spray foam in a can is that it doesn't like spraying up on a surface, but I've only tried it with the straw, perhaps from a distance with out the straw is one way to get good coverage from a can? Anyone tried ?

whatever you do it seems to dribble down until it sets, and in cool weather that could take 10 minutes. I suppose that professionals using proper spray equipment put it on in very thin layers to avoid dribble.

[jddevel]

My thoughts on the subject. There appears to be two points here. Damp is normally associated with a leak and

for example in a house produces rising moisture or penetrating moisture. Condensation on the other hand is

caused by the warm moist air in a closed space having its temperature reduced by contact with a cold surface.

Whether the "damp" conditions referred to are therefore caused by a leak or warm air in contact with a cold

surface is first to be analysed. With the information currently available from the OP I assume the problem is one of condensation. If this is the case then the installation of a vapour guard such as Tyvek Airguard may be a solution to be considered in conjunction with ventilation.

I quote

" DuPont™ AirGuard® Reflective is an airtight vapour barrier that reflects up to 95% of radiant heat, boosting thermal insulation significantly"

With my experience in the building industry I have installed both Celotex and AirGuard which I hope will keep

problems to a minimum. My only immediate difficulty is the fact that the windows installed in my sailaway were unfortunately installed as single glazed. Building to a price Mmmm!!

[stegra]

If you're going to use gun foam, get a proper gun and gun-grade foam. You have far better control, the foam goes much further and you can use as little as you wish then just close off the gun and use it again months later. No problem at all foaming to walls and even ceilings with a little practice. Don't remove the gun from the can or use gun cleaner, just immediately replace a used can with a full one.

 

On a boat it would be prudent to use fire-rated foam. The regular stuff burns fiercely and give off noxious black smoke. I regularly foam Celotex sheets to house walls and foam plasterboard to the sheets. Never had any problems. Used the same method to do a van several years ago too without any issues. Not sure I'd do a full boat that way though.

[dandandan]

My thoughts on the subject. There appears to be two points here. Damp is normally associated with a leak and

for example in a house produces rising moisture or penetrating moisture. Condensation on the other hand is

caused by the warm moist air in a closed space having its temperature reduced by contact with a cold surface.

Whether the "damp" conditions referred to are therefore caused by a leak or warm air in contact with a cold

surface is first to be analysed. With the information currently available from the OP I assume the problem is one of condensation. If this is the case then the installation of a vapour guard such as Tyvek Airguard may be a solution to be considered in conjunction with ventilation.

I quote

" DuPont™ AirGuard® Reflective is an airtight vapour barrier that reflects up to 95% of radiant heat, boosting thermal insulation significantly"

With my experience in the building industry I have installed both Celotex and AirGuard which I hope will keep

problems to a minimum. My only immediate difficulty is the fact that the windows installed in my sailaway were unfortunately installed as single glazed. Building to a price Mmmm!!

 

Yes, I am pretty confident that the problem is moist air condensating on bare steel surface where insulation is missing. I was hoping that by sprayfoaming the gaps I can provide a moisture barrier?

 

 

If you're going to use gun foam, get a proper gun and gun-grade foam. You have far better control, the foam goes much further and you can use as little as you wish then just close off the gun and use it again months later. No problem at all foaming to walls and even ceilings with a little practice. Don't remove the gun from the can or use gun cleaner, just immediately replace a used can with a full one.

 

On a boat it would be prudent to use fire-rated foam. The regular stuff burns fiercely and give off noxious black smoke. I regularly foam Celotex sheets to house walls and foam plasterboard to the sheets. Never had any problems. Used the same method to do a van several years ago too without any issues. Not sure I'd do a full boat that way though.

 

Thanks I will get one of those. Do you have a foam recommendation (this? http://www.toolstation.com/shop/p85137).

[Robbo]

Yes, I am pretty confident that the problem is moist air condensating on bare steel surface where insulation is missing. I was hoping that by sprayfoaming the gaps I can provide a moisture barrier?

 

 

 

 

Thanks I will get one of those. Do you have a foam recommendation (this? http://www.toolstation.com/shop/p85137).

Anyone have any experience of using the gun? Is it that much better than using the disposable ones?

 

http://www.toolstation.com/shop/Adhesives+%26+Sealants/d180/Expanding+Foam/sd2857/Professional+Foam+Gun/p93227

[cereal tiller]

Anyone have any experience of using the gun? Is it that much better than using the disposable ones?

 

http://www.toolstation.com/shop/Adhesives+%26+Sealants/d180/Expanding+Foam/sd2857/Professional+Foam+Gun/p93227

Have got one,buy a can of gun cleaner,it screws on in place of the Foam Canister.

 

Best to flush it through when not going to be used for a period of a week or more

 

CT

[stegra]

If you buy a foam gun you'll need to buy gun-grade foam. I've been using this for about 25 years. Once you have a gun you'll be finding uses for it everywhere. The control is so fine that I once wrote SBMCC on a two pence coin with foam to prove a point on another forum. On the other hand you can easily fill gaps a few inches wide. When you let go of then trigger, it stops; unlike the handheld stuff that keeps leaking.

 

You can leave an unfinished can on a gun for months and then start re-using it. I don't agree that the gun should be cleaned between cans. The cleaner does more harm than good. Have a can of cleaner handy in case of mishaps though.

 

I don't bother with expensive guns. I normally get several years use from the cheap ones. And none of them work if you stand on them and bend the shaft. As stated, a can of cleaner is handy so this might be a fair package but you can get guns for around £7. But stick with the metal ones.

 

Fire-rated gun-grade foam

 

Or bulk pack

 

One last point. When changing the can, make sure the old one is completely empty by holding the trigger until no more gas escapes. Then close the control knob before fitting the new can. Blow any excess foam off the gun and then put it on the new can immediately. Make sure the can is held vertically (top up) when you fit the gun and take care not to cross thread it. Normally it's necessary to push the gun down onto the can a little to get the thread to engage. In use the can should always be upside down.

[system 4-50]

Wot he said ^^^^^.

Using the cleaner is bad idea. Unless perhaps not using it for a year or more.

[stegra]

A year without using a foam gun! Nah. It's the crack pipe of builders' tools

[stegra]

Not sure if this has been mentioned in this thread but if you're going to be doing a lot then you can buy two-part closed-cell PU foam kits. If you go this route make sure you follow the instructions and don't let the bottles fall over otherwise the mix won't work. I don't know how small the kits can be but this is one I used about a year ago:

 

https://www.abbuildingproducts.co.uk/touch-n-foam---200-complete-kit-pr-5203.php

[system 4-50]

Correct me if I'm wrong but aren't professionally installed sprayfoam, diy sprayfoam as above, and gun sprayfoam all slightly different?

Not so much in the chemicals but in the total effect?

The professional method uses nitrogen propellant. The gun does not.

The professional stuff sticks on walls and ceilings, the gun stuff must be supported for a few seconds/minutes while it stiffens or it falls off, and the diy stuff looks different from pics I seen but that might just be the skill of the applier.

[stegra]

Not sure how dissimilar the DIY two-part is to the pro stuff. The gun stuff is very different; for a start it's open cell and far less dense. Gun foam will stick to walls and even ceilings with a little practice. It's best to dampen the surface first; this helps it stick and prompts the curing process. It's true that the gun foam is no substitute for the closed cell foam but it might be suitable for patching in depending on the circumstance.

 

For me, the handheld is an utter waste of time and effort. Unless the effect you're looking for is; hole still in wall, trail of foam down wall to big blob on the floor; can in carrier bag, gurgling away.

[dandandan]

If you buy a foam gun you'll need to buy gun-grade foam. I've been using this for about 25 years. Once you have a gun you'll be finding uses for it everywhere. The control is so fine that I once wrote SBMCC on a two pence coin with foam to prove a point on another forum. On the other hand you can easily fill gaps a few inches wide. When you let go of then trigger, it stops; unlike the handheld stuff that keeps leaking.

 

You can leave an unfinished can on a gun for months and then start re-using it. I don't agree that the gun should be cleaned between cans. The cleaner does more harm than good. Have a can of cleaner handy in case of mishaps though.

 

I don't bother with expensive guns. I normally get several years use from the cheap ones. And none of them work if you stand on them and bend the shaft. As stated, a can of cleaner is handy so this might be a fair package but you can get guns for around £7. But stick with the metal ones.

 

Fire-rated gun-grade foam

 

Or bulk pack

 

One last point. When changing the can, make sure the old one is completely empty by holding the trigger until no more gas escapes. Then close the control knob before fitting the new can. Blow any excess foam off the gun and then put it on the new can immediately. Make sure the can is held vertically (top up) when you fit the gun and take care not to cross thread it. Normally it's necessary to push the gun down onto the can a little to get the thread to engage. In use the can should always be upside down.

 

Thanks for this. Very useful.