Need to insulate wall. Chalet house please help check

[platforminc]

Hi All.


We have just moed into a house and we were shocked as to how much we are spending on heating. I have contacted British gas to take advantage of the free loft insulation offer. The engineer came out and now he has said that we could benefit from loft insulation, he said the preset insulation is only 50mm and it will be massively increased. However our house is a Chalet semi, so he said that the slanty section of the roof/loft is not covered under the funding. He did however explain how we could still insulate the place, I wasnt taking down notes on the day so I couldnt really understand what he meant over the phone.

The master bedroom leads to the loft storage area, its always cold and this is affecting how much heat can be retained in our bedroom. He did say that one part of the loft storage room can be insulated, we already have the underneath of the tiles insulated, but he also said you cant have floor insulation (under floorboard) and somewhere else insulated due to vapour issues or something like that.

Now I had a look when I got back from work that day and at night, its almost like the batterns flow with cold air and to me, it looks like an easy win, if i can get the rock wool insulation, I can fill up the batterns and then board it up.

I just wanted to know if anyone agreed with my solution. I feel this will help until such time that the actual loft will be insulated.

Thanks in advance.


This is the outside

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• platforminc
• 21 Nov 2014
• 1

This is the area that i want target, the batterns.

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• platforminc
• 21 Nov 2014
• 1

Section of the loft

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• platforminc
• 21 Nov 2014
• 1

Existing insulation

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• platforminc
• 21 Nov 2014
• 1

 

[tony1851]

Can't quite relate the description to the pics, but that may just be me.

The glass wool pushed up against the tiles and then boarded under is not good - it cuts off air circulation and can cause condensation issues.

 

[platforminc]

any issues with puting a 100mm insulation between the batterns ?

 

[freddiemercurystwin]

Can't quite relate the description to the pics, but that may just be me.

Your post is pretty confusing, that's why there's been so little response.

 

[platforminc]

Simple question, can I put rockwool insuluation in between the batterns in the second picture and also the 4th picture to your left, there are some battenn there also which backs onto the living room.

Want to know if I can have insulation there also.

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• platforminc
• 25 Nov 2014
• 1

So technically in this picture above, the slanting roof section is the section labelled as cupboard in the picture above. The cupboard is usually very cold and also the plasterboard in room 1 which backs to this cupboard (where the door leading to the cupboard is) is very thin and often cold from the room as well. so I reckon insulating this wall will also help.

 

[Bilabong007]

You are missing the difference between cold and warm lofts.

If you are trying to insulate the rooms I would opt for a cold loft area which is ventilated. The insulation goes on the walls/ceilings between the lofts and habitable spaces. This way avoids condensation.

Don't try and keep the loft warm by insulating the roof structure. Insulate the stud walls on the left of pic 2 and 4.

Don't use rock wool, use celotex or kingspan or the likes and fit it correctly.

Do you have ventilated eaves or tile vents?

Graeme

 

[platforminc]

thanks very much. I will get over to wickes to buy the boards. I am guessing to fit them, one just has to measure the distance between the wood beams for the stud wall, cut the board into place, fit into the stud wall.

I also intend to cover with some white hardboard type material. Any concerns with my plan ?

 

[Bilabong007]

None other than you need to ventilate the loft.

The glass wool stuffed between the rafter should really be removed. It will cause condensation to be trapped at the rafters and is an ideal situation for rot.

The hardboard won't do much except make it look nice. It's all about U values and it won't add much to that overall

Fitting the celotex can be done in two ways:
1. Really accurate cuts to size and friction fit between the stud work.
2. Cut it small and fill gaps with expanding foam.

I prefer 2 as it's easier to make a good seal and avoid cold spots on the inside of the stud wall.

I fitted 50mm celotex and calculated it would reduce heat loss through the wall by 70%. Thicker celotex obviously reduces this more, but the returns diminish, iirc 100mm celotex gave 90% reduction.

I have a pic of my work in my album

PIR first fit

• Bilabong007
• 1 Mar 2014
• 2

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• Bilabong007
• 1 Mar 2014
• 2

Hope this helps

Graeme

 

[platforminc]

Point noted.
If you look in picture 2. That stud wall backs into bedroom 2 and also forms part of the walls in room 2. Should this be insulated as well ?

That room is my kids room and it also becomes quite cold as well for no reason.

 

[platforminc]

Also the depth of the stud walls is 100 mm. Any issues with using 100 mm celote?

Also where there are cables.i can just use expanding foam to fill the gaps.

 

[platforminc]

Thanks all.
I have now used a 100mm celotex insulation. One thing I'm not sure of is how to insulate the door leading to loft cupboard.

Also, I'm keen to board it up. Any issues

 

[OuterSpaceHopper]

Hi,
Do you know if your loft is a warm or cold loft? I know virtually nothing about building or roofs and so don't recognize the sheet material above your rafters in the last photo. Is it breathable, or ventilated?

I think the regulations say that for a cold loft, you need to retain 50mm of airflow out of the eves and up the rafters to keep condensation down.

In the first photos, it looks like the area behind the white ?plaster board? between he rafters has been insulated with fibreglass. This may cause you condensation problems behind the board, especially if the roof membrane is not breathable. This could lead to rot.

If your not sure if you have a warm or cold loft it might be worth finding out or taking this stuff out.

A mate of mine insulated the rafters in the loft, just to keep the loft free of the bitumin dust from the roof membrane. He later found condensation collected behind the foil sheeting and made the rafters wet. He ended up taking it out.

I can see that the area above you inner room has space for some insulation and since heat rises to the ceiling it might be worth insulating this, so long as you maintain the 50mm of ventilation above any insulation you add. With a wooden pusher, you could slide PIR or soundboard sheets up there.(http://www.wickes.co.uk/Wickes-30mm-Acoustic-Insulation-Slab-3-6m2-Pack-5/p/161189)

I added insulating sound board(30mm I think) down the eves of my house as I noticed quite a bit of road noise comes through the ceiling plaster board eves and also noticed that the neighbors have damp patches on the eves in the bedrooms as moisture in the house condenses on the cold plasterboard where the back of the board is effectively at outside temperature.
There is still enough space for air to pass through the softit vents, up the eves for ventilating the rafters and loft.

 

[platforminc]

I have now insulated the wall to your left in picture 4. It ow looks like Billabongs work.
I do have a cold loft it looks like. I'm not sure if the insulation behind the roof felt/tiles is supposed to be there. This is what we met when we moved in.


The house still looses heat an alarming rate, the next thing we are tackling is the loft insulation. It's really really low with some areas not having insulation I believe.

not sure if it would make a difference, but it's just really weird. The previous owners have a open gas fire in the dining. As we have a baby in the house, it's not safe to use.

The door leading to the loft cupboard is one that I'm also keen to look at.

Thanks in advance

 

[Grenage]

As others have already said, the information is a little unclear.

Assuming you have a cold loft (and I'm guessing you do), you probably want to remove that little section of plasterboard and fibreglass betwixt the rafters.

Insulate the stud walls externally, where you can (as you've started), insulate the ceiling of the room (not the loft) externally if possible - externally if not.

Regarding the cupboard, you could incorporate it into the rest of the room but insulate the cupboard boundary. The Celotex would need to go on top of the rafters, rather than between them, and I assume it would only be an option if there was ventilation at the eaves. If you did so, you'd probably also want to incorporate a vapour barrier.

Failing that, you could just affix insulation board to the back of the door, and staple bagged fibreglass to the hinge side.

Regarding talk of expanding foam around cables - no.