DIY insulation

[johnmac1979]

Hi all. Some advice required please.

I'm a pretty competent DIY'er.

I've got a 1900's Farmhouse in Perthshire, Scotland.

The house has absolutely no wall insulation. I put 15" of fibreglass insulation in the loft last year were previously there was none. I've also fitted a multifuel stove in the dining room 18mths ago, and completely re-rendered the two storey gable end of the house 18mths ago. The render was blown and there was a slight damp issue, now completely resolved!

Next step is to start insulating from the inside. The dining room has horrible 'chip board' nailed onto 1" battens with no insulation behind... Just a two course red brick wall behind. It's the coldest part of the house. I'm able to get the room to 20oC purely with the stove on but as quick as the heat is up... It's getting sucked out through the walls.

So... (bear with my rambling!) I want to remove the horrible chipboard and batons and replace them with either 4"or 5" x 2" batons, fill them with 4" or 5" kingspan from 'seconds and co' and then plasterboard... Probably with foil backed plasterboard???? In the hope it'll greatly increase the insulation of the room and this increase the temperature of the room and with it the rest of the house!?!?

A friend of a friend (yes, that old chestnut!) who is a builder says don't do it, it'll cause damp?!? Personally I think he's talking guff! Because everytime I watch grand designs and see people renovating old properties they put up batons, slot in kingspan and then plasterboard over the top?!?!?

So (finally getting to the point!)

1st. Is kingspan a suitable insulation for such a project?

2nd. What issues might I create damp wise, if I put Kinspan in??

Should I plastic sheet the wall first?

This room has four 'breather bricks' on the outside wall. Should I leave these open, ie not cover with kingspan? To allow air flow this reducing any potential damp???

All and any info most welcome! I've searched other posts but haven't yet come across a similar question.

Thanks in advance!

 

[johnmac1979]

Ps. The wood burner is on throughout the winter and at least once a week throughout the year. Surely this warm 'dry heat' would eliminate any potential moisture problems anyway?!?

 

[mointainwalker]

1st. Is kingspan a suitable insulation for such a project?

Yes

2nd. What issues might I create damp wise, if I put Kinspan in??

None

Should I plastic sheet the wall first?

No

Probably with foil backed plasterboard????

Yes and tape the joints so it acts as a vapour barrier.

I've searched other posts but haven't yet come across a similar question

Really ???????? Everything you have asked is completely standard.

 

[johnmac1979]

Thanks for the straight to the point replies!

Clearly I didn't look hard enough.

Lastly, I think you have confirmed what i suspected about my friends 'builder' he isn't the genius he believes he is.

 

[catlad]

I feel sure if you google kingspan they will have the technical info on there web site.

 

[lawlor]

Hi,
I have recently insulated a bathroom that is of the same construction as your room but it was just plastered before. I didnt use a floating stud wall but followed the guide on http://www.celotex.co.uk/applications/refurbishment/external-solid-walls
the reason for this is that you tape the Celotex joints which creates your vapour barrier. The other problem i read about when using a floating stud wall is that it creates thermal bridging and you need to put 25mm over the before you plasterboard- but this might be wrong - but does seem reasonable

So i had 50mm celotex then 25x50mm battons then vapourshield plasterboard which i only used as was in a bathroom and when i do the next rooms ill use normal stuff.
Its made a HUGE difference its went form being coldest room in house to warmest.

Hope this helps.

 

[johnmac1979]

Than for the link and the info! Very helpful. Can anyone tell me what is the recommended amount of Kingspan to use?!? I'm sure there's a 'government standard' ?? Like I said before I'm thinking of going for 100mm or 125mm Kingspan.... Is that seriously over gunning it?!? Or if I can afford it and don't mind losing as extra few inches of room is it worth going way over the top?

Thanks

 

[lawlor]

not sure what the recommended is, again on celotex site i think it tells you all. i used 50mm as that combined with 25mm batten and 12.5mm PB was about 4inches which is alot to loose. I remember that modern standards is about 100mm but i suppose it would depend on where you are(and thus temp) to wether you would need more than the 50mm i used. I think on all the methods you need an air-gap between the insulation board and your PB.

Also if price is a consideration, foil taping the insulation board joints and then attaching them to the wall with battens and then normal PB on top will save you quite alot when you keep in mind the price of battens vs 2x4 and normal PB vs vapour

again hope this helps.
Im not an expert just saying what i have done. and its working well for me!

 

[mointainwalker]

I think on all the methods you need an air-gap between the insulation board and your PB.

Unnecessary waste of space. Pb on insulation and (recommended) space between insulation and wall.

 

[lawlor]

Im just saying what the manufactures say when you use separate PB and insulation. the other benefit of leaving an airgap is that you can attach stuff to the battens shelves etc, or to the PB without damaging your vapour barrier