Insulating a Crawl Space

DampCat

DampCat

DampCat

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Leafy Cheshire
I've just discovered that one of my bedroom walls is completely uninsulated. I've drawn a crude diagram this:

Screenshot-20221217-114648.png


The blue line is the bedroom wall. Behind it is a crawl space. That wall is just plasterboard screwed to some batons and nothing behind it and when you stand near it you can feel the cold permeating through. I have built in wardrobes on that wall and my clothes are freezing when you put them on.

What's my best option for insulating? The hatch for the crawl space is very small, I'm not sure I can get kingspan up there. Is it just a case of using some rolls of insulation between the batons? Do i need to plasterboard over the insulation in that case?

There's also a load of uncovered pipes up there for the hot water. Bleeding British gas
 
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Your best bet would be to take off the plasterboard from the back of your wardrobe and insulate it from the bedroom side. That way you're just cutting the boards to fit in between the vertical timbers. If the wardrobe is full width of your room you hopefully won't have any cables etc to interfere with? Going in by the hatch i assume that the size wouldn't allow the boards to be slid in one piece and fitted between the vertical timbers and it would probably be cut into two or three pieces to do the same job?

Also why are you blaming british gas for uncovered pipes? Wouldn't that have been the plumber's fault?

EDT :-

I assume you've got insulation in the sloping part of your ceiling?
 
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Fit PIR boards between the batons accessed through the hatch? Assuming 400mm spacing the hatch will be bigger than that.

Tape the joints. Absolute worst case then do a second lot perpendicular to the first?

Then also lag the pipes, could insulate above the garage too just using rock wool.
 
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Because British Gas installed the new boiler and hot water cylinder in the garage from the old location in the airing cupboard upstairs. They still haven't wired in the immersion heaters after 2 years of calling once a week. It was they who routed the new pipes through the crawl space into the loft and left them unlagged.

It's a monumental task as the wardrobes are part of the wall, not like a wooden system built to fit. I'd have to destroy the wall and rebuild and replaster it to insulate from this side. If that's the only option then I'll just have to live with it until we can take on that level of work. On the other side it's empty so I was just hoping it could be done from there. I could just cut the insulation board into many pieces to get through the hatch if that's not going to ruin any thermal properties
 
I have a similar crawl space. The previous owner put the normal roll insulation stuff vertically between the studs, and then screwed horizontal batons across to hold them in ( 3 or 4 was all that was needed, I’d need to check ). That would be not too hard to manage in the crawl space?. Its not perfect, but good enough compared to having nothing.


You could pre-cut the lengths of rolls, and the batons and that should be simple enough to get through the gap.
 
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I would insulate the roof so your pipes don't freeze.
But what about the floor? I assume that isn't insulated either? It may be a good idea to insulate the roof in the garage too.
 
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lag the pipes, cheap enough, I dont understand what's wrong with Pipes running somewhere you don't see tho?
Surely they discussed the install with you? As for the waiting 2 years...
Did you pay any of the install costs (even the deposit) via CC? Or did they provide a Credit agreement?


And the insulation, can you fit in the crawlspace at all? If so I'd be looking at Celotex or kingspan type products.
I'd not in a month of sundays be in a space that big faffing about with standard fluffy insulation
 
Do you need to tape the joins how crucial is that?

Can I lay kingspan horizontal on the floor?

I have similar crawl space that opens up into some weird little room behind the bathroom
 
LabR@t said:
Do you need to tape the joins how crucial is that?

Can I lay kingspan horizontal on the floor?

I have similar crawl space that opens up into some weird little room behind the bathroom
Click to expand...
Kingspan, tape and then grow weed imho.
 
Taping joints isn’t crucial it it will help. The less cold air you have going in to the space the more warm air will remain. Cumulatively it may add up to a bigger area than you may realise.
 
None of this was supposed to be about the pipes. I don't have a problem with the pipes being there and not sure where I said I did. The small issue is they're unlagged in an uninsulated area. I will lag them. Frustrated with people not doing their job properly.

I will cut PIR board into smaller pieces to get through the hatch, place and tape them. That seems the easiest solution (lots of cutting). The crawl space floor is already rockwooled to 250mm so that should be fine.

Can I use PIR for the underside of the roof in that part? Or is that not necessary?
 
You can use PIR anywhere, just be careful to not block it in completely if it has no specific way to let that area breath.
You need some air circulation or you will create in effect a sealed area that will allow damp in without a way to escape

Better to insulate the pipes, and the back of the wardrobe wall (ie inside crawl space) and maybe a bit on the roof but keep it semi open. Insulating the underside of the roof will also help keep heat out during the summer.
You can also buy a foil backed bubble type insulation that you simply staple onto the joists for that purpose, like this https://www.wickes.co.uk/Wickes-Thermal-Foil-Insulation-Roll-600mm-x-8m/p/210022
 
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