insulation behind skirting boards

LinoRichie

Hi,

Advice appreciated. I have a 3 bed SD house, approx 17 years old. Excuse my un-technical terminology here but the walls consist of one layer of cavity blocks, a gap, a couple of inches of insulation (looks like the stuff you'd see a stereo or tv packed in) and plasterboard. I know this is probably quite poor insulation wise but I'd like to do as best I can with it.

We are doing a bit of renovation at the moment. I've recently had the walls skimmed and as part of this process I pulled all the skirting boards off.

In most places neither the plasterboard or insulation reach the floor and I can see the bricks through where the skirting was. There is a few inches gap between the floor and the bottom of the skirting and insulation.

Before I put new skirting back on, has anyone any recommendations regarding this? Would it make much difference trying to do something insulation-wise here? Can I use some kind of foam? If I do something should I try and maintain the gap between the bricks and whatever insulation I use?

Cheers.

kkelliher

you can easily use an expanding insulation foam. Put it on a day or so before the skirting so it doesn't push off the skirting. Cut it then put on the skirting.

It wont help massivly but every bit helps. it will also stop any draft coming down the insulation into the room.

You should have put up thermaboard if you were going to be plastering anyway. It would have helped greatly with your insulation.

Slig

It sounds to me like the house is built of cavity blocks and dry-lined.
If possible then there should be insulation behind the skirting but it depends on how much of a renovation you want to do. It would be best to remove the plasterboard in this area an either replace with new insulation backed plasterboard or put insulation between the battens and new plasterboard over it. Depends on what method of drylining was used originally.

The spray foams arent designed to be insualting, they swell while drying and they decay so they arent suitable for this application.

buck65

what about an insulated slab?
cut into strips and stuck on
you can get this product 25mm thick upwards

LinoRichie

Thanks for the prompt and helpful replies

It sounds to me like the house is built of cavity blocks and dry-lined.
If possible then there should be insulation behind the skirting but it depends on how much of a renovation you want to do. It would be best to remove the plasterboard in this area an either replace with new insulation backed plasterboard or put insulation between the battens and new plasterboard over it. Depends on what method of drylining was used originally.

The spray foams arent designed to be insualting, they swell while drying and they decay so they arent suitable for this application.

To be honest, removing and replacing the plasterboard is not an option, I've just had the existing plasterboard skimmed. Do you recommend any alternatives to the foam?

what about an insulated slab?
cut into strips and stuck on
you can get this product 25mm thick upwards

sorry to be a total idiot but what is this insulated slab you speak of? i've googled it but i'm not sure i'm seeing exactly the thing you're talking about...

Slig

sheets of plasterboard are called slabs. some plasterboard "slabs" have a sheet of insulation stuck to the backs of them.

are there any battens visable where the skirting boards were? What were the skirting boards fixed to?

sinnerboy

LinoRichie wrote: »

To be honest, removing and replacing the plasterboard is not an option, I've just had the existing plasterboard skimmed. Do you recommend any alternatives to the foam?

Whilst slig is right - foam is not ideal - it is probably the most practical thing for the situation as you describe it . It is worth doing .

Practical tips

- it really does EXPAND . Do a small length first - say 300mm long and wait for 30mins ...
- let it go off first before trimming back . ( 24 hours ) invest in a really sharp stanley knife no Eurosaver special
- this stuff sticks to skin like you would not believe - wear gloves
- take your time - don't rush the job

LinoRichie

Slig wrote: »

sheets of plasterboard are called slabs. some plasterboard "slabs" have a sheet of insulation stuck to the backs of them.

are there any battens visable where the skirting boards were? What were the skirting boards fixed to?

ah, i see. i think i may have slabs already in place then, do i? i have sheets of plasterboard with a few inches of insulation behind them.

Just to clarify, I'm only talking about filling a few inches between the floor and the bottom of the plasterboard and insulation - can i still use new slabs here?

The skirting was nailed to the plasterboard before I removed it.

I don't think there are battens visible, I'll have to check this evening though. The plasterboard and insulation has blobs of mortar(or something) behind it attaching it to the external blocks.

Whilst slig is right - foam is not ideal - it is probably the most practical thing for the situation as you describe it . It is worth doing .

ok but is the gap between the insulation and the blocks not important in insulation and keeping dampness out? should i not try to keep a gap between the insulation (i.e. foam) and the bricks or is this not important?

Slig

LinoRichie wrote: »

ah, i see. i think i may have slabs already in place then, do i? i have sheets of plasterboard with a few inches of insulation behind them.

Just to clarify, I'm only talking about filling a few inches between the floor and the bottom of the plasterboard and insulation - can i still use new slabs here?

The skirting was nailed to the plasterboard before I removed it.

I don't think there are battens visible, I'll have to check this evening though. The plasterboard and insulation has blobs of mortar(or something) behind it attaching it to the external blocks.

ok but is the gap between the insulation and the blocks not important in insulation and keeping dampness out? should i not try to keep a gap between the insulation (i.e. foam) and the bricks or is this not important?

It depends if the drylining is there because there was moisture coming through the wall or because the original inhabitant wanted a little more insulation. In a damp environment the expanding foam will last about a year before it decentigrates however it would be the cheapest and easiest option.

LinoRichie

It depends if the drylining is there because there was moisture coming through the wall or because the original inhabitant wanted a little more insulation. In a damp environment the expanding foam will last about a year before it decentigrates however it would be the cheapest and easiest option.

The drylining was done when the house was first constructed. There is no problem with dampness as far as I can tell. Maybe I'll go with the foam so unless there's something i can do with slabs?

buck65

go for the insulated plasterboard
kingspan tw52 or equiv.
use a bonding compound to dab it onto the wall or a metal thermaboard fixing to drill it directly onto the wall.
cut the sheets into 100mm or whatever strips and work away.
aprox price €30 per sheet 2.4mx1.2m
compound €8 per bag
fixings 20c each

PaulieBoy

There is always a gap between the floor and the bottom of a slab, it's normal!
When sticking the slabs to the wall you use a shovel to hold the slab up tight to the ceiling, then stick a wedge in under it till it sets.
I'm surprised none of the above bothered to mention this well known fact !!!!!!

Heat rises, the net heat loss between this gap would be tiny.

Forget about using foam ( a stupid suggestion), that would be a complete mess, just get some type of insulation, any type and stick it in the gap ( if you must).
Some attic insulation would do the job nicely.

On a scale of 1 to 10, this "problem" is a about 1/4 of one percent :-)
I'd forget about it, if I where you, just stick the skirting's back and move on.

sinnerboy

Better not come across me IRL Paulie boy . Stopped payments , opening up works and snags galore for you my friend if it ever happens

Slig

PaulieBoy wrote: »

There is always a gap between the floor and the bottom of a slab, it's normal!
When sticking the slabs to the wall you use a shovel to hold the slab up tight to the ceiling, then stick a wedge in under it till it sets.
I'm surprised none of the above bothered to mention this well known fact !!!!!!

Heat rises, the net heat loss between this gap would be tiny.

Forget about using foam ( a stupid suggestion), that would be a complete mess, just get some type of insulation, any type and stick it in the gap ( if you must).
Some attic insulation would do the job nicely.

On a scale of 1 to 10, this "problem" is a about 1/4 of one percent :-)
I'd forget about it, if I where you, just stick the skirting's back and move on.

Sure as long as you get the job half done it grand:rolleyes:.

The OP has asked for help solving a problem. many posters here have given suggestions. The gap may be normal with piss poor building practices but there is no point in insulating a wall if there are gaps in the insulation for the heat to escape. Why would you intentionally leave a huge cold bridge all around the perimeter of the building.

Jesus I really wish we could weed out some of the chancers we have calling themselves builders. "Dont listen to the professionals, I've been doing it this way for years"

muffler

PaulieBoy wrote: »

There is always a gap between the floor and the bottom of a slab, it's normal!
When sticking the slabs to the wall you use a shovel to hold the slab up tight to the ceiling, then stick a wedge in under it till it sets.
I'm surprised none of the above bothered to mention this well known fact !!!!!!

Heat rises, the net heat loss between this gap would be tiny.

Forget about using foam ( a stupid suggestion), that would be a complete mess, just get some type of insulation, any type and stick it in the gap ( if you must).
Some attic insulation would do the job nicely.

On a scale of 1 to 10, this "problem" is a about 1/4 of one percent :-)
I'd forget about it, if I where you, just stick the skirting's back and move on.

Stick to your day time job as this effort at humour doesn't really work that well.

RKQ

LinoRichie wrote: »

I don't think there are battens visible, I'll have to check this evening though. The plasterboard and insulation has blobs of mortar(or something) behind it attaching it to the external blocks.

Sounds like dry-lining on Plaster dabs. This detail requires a "firestop" around the perimeter of the wall - either timber batten behind the skirting board or strip of adhesive.

OP should look at this for details http://www.insulateonline.com/index1.htm?walls3.htm~main

So in summary - there should not be a gap!

PaulieBoy

muffler wrote: »

Stick to your day time job as this effort at humour doesn't really work that well.

No attempt at humor! If it where you would know.

LinoRichie

jaysus lads, i didn't mean to cause an argument!

thanks for all the feedback

had a look at the walls again last night...the gap between the bottom of the plasterboard / insulation and the floor is quite small downstairs, maybe a few centimetres so i might just use the foam there...i could feel a light draught with my hand there...

upstairs the gap is quite large maybe 4 or 5 inches so maybe i'll try and do something with the insulated plasterboard there...

i went into woodies on the way home yesterday to have a look at insulated plasterboard but they didn't have any just the normal un-insulated plasterboard...where would i get it?

cheers

RKQ

Most Builders Merchants / Hardware with have insulated plasterboard slabs.

Use Plaster Adhesive or a timber batten to Firestop the wall first - otherwise in the event of a house fire the flame will get behind the slab, melt the insulation (creating a sticky highly flamable Napalm solution) and spread very quickly behind the slab. The insulation will act as a liquid fuel!

Firestop then insulate the gap!

LinoRichie

RKQ wrote: »

Most Builders Merchants / Hardware with have insulated plasterboard slabs.

Use Plaster Adhesive or a timber batten to Firestop the wall first - otherwise in the event of a house fire the flame will get behind the slab, melt the insulation (creating a sticky highly flamable Napalm solution) and spread very quickly behind the slab. The insulation will act as a liquid fuel!

Firestop then insulate the gap!

Just getting back to this now, thanks for the feedback, this site and the contributors on it are great

2 questions:

1. If i use adhesive to firestop the wall, would this adhesive suffice for bonding the insulated plasterboard to the blocks (bearing in mind that we're only talking a few inches in height of plasterboard) or would i need some other bonding compound as well?

2. Can I definitely saw the insulated plasterboard into strips? I was in a builder's merchants and one of the guys there thought the plasterboard might disintegrate if I cut it.

RKQ

LinoRichie wrote: »

1. If i use adhesive to firestop the wall, would this adhesive suffice for bonding the insulated plasterboard to the blocks (bearing in mind that we're only talking a few inches in height of plasterboard) or would i need some other bonding compound as well?

Bonding adhesive should be fine for both jobs. Check with manufacturer to be sure.

LinoRichie wrote: »

2. Can I definitely saw the insulated plasterboard into strips? I was in a builder's merchants and one of the guys there thought the plasterboard might disintegrate if I cut it.

Cutting strips a few inches in height shouldn't be a problem. Cut strips 1200mm wide might be easier to cut. These 1200mm strips would be easier to fit, to ensure a full firestop and bond along the 1200mm length.

GreeBo

[QUOTE=PaulieBoy;58963422 you use a shovel to hold the slab up tight to the ceiling,

Heat rises, the net heat loss between this gap would be tiny.

Forget about using foam ( a stupid suggestion), that would be a complete mess, just get some type of insulation, any type and stick it in the gap ( if you must).
Some attic insulation would do the job nicely.

On a scale of 1 to 10, this "problem" is a about 1/4 of one percent :-)
I'd forget about it, if I where you, just stick the skirting's back and move on.[/QUOTE]
Where to being with this one?

As you rightly pointed out, heat rises, the corollary of this is that cold air falls. Thus the cold air from upstairs will fall down this gap to downstairs.

Also, its a fact of physics that heat moves towards colder things, whether it be conduction, convection or induction its a fact.
Having the external brickwork exposed in your rooms is not desirable for these reason.

As long as the gaps are at least more than 1 inch wide Id batten them and then attach either plasterboard or some plywood (WBP) to the battens. Any gaps after the battens you can fill with foam before you cover. Then you can just reattach the skirting.

If nothing else at least this removes the vent your rooms all currently have!