# Thickness of insulation when drylining



## Shawady (5 Mar 2010)

We moved into a house a couple of years ago that was built in 1970. At the time we were advised by our surveyor we would have to internally dryline the front and back walls.
We are now getting some work done to the house and plan to do it, but in order to get the SEI grant we have to use insulation of 100mm thickness. Another critera required for the grant is that we dryline 3 sides of the house, although the house is terraced.

Someone mentioned to me that 100mm may be over the top and costly so I was wondering would insulation of say 30 or 50mm do a sufficent job and would drylining one side wall be a waste of time just to get the grant?


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## Sconhome (5 Mar 2010)

It has all to do with the type of existing block / masonary wall. To achieve the SEI guidelines in most cases a minimum of 70mm insulation is needed. You can decrease it along the wall of a staircase for example where, you can not over shoot the stair stringer.

Only exposed walls have to be completed, you do not have to insulate party walls as these are not considered to contribute to heat loss.

My recomendation would be to go with external insulation in a terrace house as you will have quite a small surface area when you consider doors and windows. You also will not have to replace, skirting, window boards, sockets, radiators, curtains etc


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## Barney Magoo (5 Mar 2010)

Hi Sconhome, 
Can you tell me where to get this 70mm fiigure. I can't see any mention on the specification document produced by SEI. 
I have been told that 50mm is sufficient. I'll be upgrading my internal insulation soon as part of a refit and want to make sure the contractor can be shown chapter and verse if possible. Thanks.


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## Sconhome (6 Mar 2010)

There are national guidelines on the SEI website. I tried to access them this morning, but it is opening as a corrupt document on my PC.

There is a requirement of achieving an average U-value after the improvement in the wall structure. As far as I can remember it was in the region of 0.27 was the target level.

As I said previously it depends on the structure of the wall you are improving as different materials give varying base levels. Your SEI registered contractor should be doing the sums on this before specifying the thickness of the insulation board required.

In most cases you will need 70mm insulation on the walls, up to 100mm in some cases. Thinner boards which are higher density insulation (double price) may achieve the same insulation properties over less depth.

Each situation is unique, but in the main 50mm boards (assuming standard U-values) will not achieve the recommendations set by SEI.


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## onq (6 Mar 2010)

Shawady said:


> We moved into a house a couple of years ago that was built in 1970. At the time we were advised by our surveyor we would have to internally dryline the front and back walls.
> We are now getting some work done to the house and plan to do it, but in order to get the SEI grant we have to use insulation of 100mm thickness. Another critera required for the grant is that we dryline 3 sides of the house, although the house is terraced.
> 
> Someone mentioned to me that 100mm may be over the top and costly so I was wondering would insulation of say 30 or 50mm do a sufficent job and would drylining one side wall be a waste of time just to get the grant?



Have a read.

[broken link removed]

HTH

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.


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## Sconhome (6 Mar 2010)

[broken link removed]Specifically the Wall Insulation Information

[broken link removed]


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## Vincenzo (6 Mar 2010)

The grant from the SEI for (EXTERNAL)   wall insulation is for 4000 euro . This is for the external walls, so in your case the front and back walls.
This is to provide insulation to the external wall of your house to a level which will achieve a U-value of 0.27 W/m2K . 
This U-Value could be achieved with different thicnesses of insulation depending on the R-Value of the insulation chosen.
Firstly find out which type of wall you have. Cavity , cavity block, solid etc.
You can eliminate one or more as in my case , where my house was constructed with the dreaded cavity block. so i eliminated cavity injection.
Then you can decide system to go for . Cavity injection , internal dry lining , external insulation .

I'd recommend external as there is no intrusion to your home. loss of space, moving wardrobes ,kitchen presses etc.

Ensure the contractor is registered with SEI . The product should be NSAI approved.

Vincenzo.


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## onq (7 Mar 2010)

Sconhome said:


> Specifically the Wall Insulation Information
> 
> [broken link removed]



Thanks for this Sconhome.

I could NOT find it yesterday.

Perhaps if the site said "required level of insulation in building elements" as opposed to "measures"...

Ho hum.

Thanks again.

ONQ.


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## Shawady (9 Mar 2010)

Vincenzo said:


> This U-Value could be achieved with different thicnesses of insulation depending on the R-Value of the insulation chosen.


 
Thanks for comments.
This seems to be the important point for me, that the thickness of insulation required will be dictated by what material will give me the required U-value.


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## s.r (25 May 2010)

hi new to this i was thinking of doing my hall stairs and landing areas internally i was thinking of spot sticking plus fixings to my existing slabs which are stuck to 9inch cavatiy block i was considering useing 50mm slabs can anyone advise me on this i no its a lot of work and external would be cleaner and less hassle but i just cant afford this option i also cant afford to do whole house i would appreciate any advice even the smallest thing i might not be thinking of...thanks


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## HarrySydney (20 Jul 2010)

Hi all, I'm in the same boat, bought an old house with a mass concrete back wall an the rest is mass stone. I need to decide between external and dry lining. at the moment leaning towards external due to the loss of space in the rooms and the mass concrete holding onto moisture... any advice?


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## Shawady (21 Jul 2010)

We have just had our house dry-lined. We went for the internal dry-lining although the external version is even better (but more expensive). We have not moved back in yet so I cannot say what effect it will have re: heating bills.
I was intially worried how it would look when the wall was replastered, but you would not even know the drylining boards were on the wall. The plasterers did a very tidy job and were SEI registered. If you want their contact details I can pass them on.


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## jaykayphd (21 Jul 2010)

Hi Shawady

Yeah could you post the details of the contractor you used for the drylining?  Also what area of the country are you in and roughly how much did it cost for your sized dwelling?

Thanks


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## RKQ (27 Jul 2010)

geraldodwyer said:


> bought an old house with a mass concrete back wall an the rest is mass stone. I need to decide between external and dry lining.


 
Maintain an air gap between natural stone & new internal dry-lining - 30 - 50mm.
IMO this air gap helps prevent mould. It also can be used to plumb walls as stone is rarely perfectly plumb.

Natural stone with lime mortar can allow water penetration on exposed sites during heavy rain.


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