Interior or exterior insulation?

Ryanciaran

Hi,
I'll be renovating my bungalow soon. It's 35 years old. Can i get your thoughts on whether I should use insulated plasterboard slabs inside, on all the exterior facing walls or use external plaster insulation( I don't know much bout this type) outside? The house is very cold so any advise on this would be great. I will be replacing the single glaze wooden windows also with double or triple glaze, any thoughts on which to use?
Cheers

Dardania

Personally I believe External is far superior.

Check out the grants available: http://www.seai.ie/Grants/Better_energy_homes/

MicktheMan

Ryanciaran wrote: »

Hi,
I'll be renovating my bungalow soon. It's 35 years old. Can i get your thoughts on whether I should use insulated plasterboard slabs inside, on all the exterior facing walls or use external plaster insulation( I don't know much bout this type) outside? The house is very cold so any advise on this would be great. I will be replacing the single glaze wooden windows also with double or triple glaze, any thoughts on which to use?
Cheers

External is far superior to internal. Period.

Also, as you will be changing your windows (go for triple) you have a great opportunity to do a fantastic job by installing your new windows first, flush with or proud of the outer wall surface so that the ewi will overlap the window frames. This eliminates a major thermal bridge at the heads/reveals and leaves a nice deep window sill on the inside.

Finally, don't forget to air tighten the window frames to the walls and if good air tightness is achieved, your ventilation method will need to be decided.


Do all this correctly and you won't believe the improvement it will make to the house.

BryanF

External

cpoh1

External has plenty of drawbacks also -

Limited finish options with render
Poor durability if you have kids (you can puncture the plaster finish easily)
Relocation of pipework etc.
Longevity of the product is yet to be challenged!

Internal and cavity insulation is more efficient assuming no thermal bridges, dew point is considered and finished well etc.

If you are stripping the whole house anyway its not a straight cut answer and would really depend on the house.

shedweller

How much more energy/money does external save? It is (or used to be?) more expensive than all other forms of insulation. Genuine question.

BryanF

cpoh1 wrote: »

External has plenty of drawbacks also -

1. Limited finish options with render
2. Poor durability if you have kids (you can puncture the plaster finish easily)
3. Relocation of pipework etc.
4. Longevity of the product is yet to be challenged!

5. Internal and cavity insulation is more efficient
6. assuming no thermal bridges,
7. dew point is considered and finished well etc.

8. If you are stripping the whole house anyway its not a straight cut answer
9. and would really depend on the house.

1. Plenty of options
2. Just put a mesh to a height of 2m in trafficked areas
3. Yes you need to move pipe work out by thickness of insulation
4. The better manufactures will give long guarantees and isn't there an Irish manufacturer who has it installed since the 60's - unlit knelt the devil is in the detail
5. please explain how drylining is more effecient?
6. As above please explain how you avoid thermal bridges with drylining?
7. Why not explain the parameters of drylining in relation to due point?
8. loosing floor area, because your decorating anyway?
9. Agreed

BryanF

shedweller wrote: »

How much more energy/money does external save? It is (or used to be?) more expensive than all other forms of insulation. Genuine question.

On what a % basis v drylining ?
As cpoh1 suggests it's a house specific answer and one that should account for comfort & Heath issues.

shedweller

BryanF wrote: »

On what a % basis v drylining ?
As cpoh1 suggests it's a house specific answer and one that should account for comfort & Heath issues.

Ah yes thats what i meant. I suppose its hard to put a figure on it. You'd have to have two houses beside each other in the same estate to get a good solid figure on it.

BarneyMc

External is best, no question.

JonathonS

On some houses the addition of external insulation can change the shape of the overall structure such that it no longer looks "right". An architect pointed this out to me, and since then I have noticed externally insulated detached bungalows in particular where the proportions jar on the eye.

cpoh1

BryanF wrote: »

1. Plenty of options
2. Just put a mesh to a height of 2m in trafficked areas
3. Yes you need to move pipe work out by thickness of insulation
4. The better manufactures will give long guarantees and isn't there an Irish manufacturer who has it installed since the 60's - unlit knelt the devil is in the detail
5. please explain how drylining is more effecient?
6. As above please explain how you avoid thermal bridges with drylining?
7. Why not explain the parameters of drylining in relation to due point?
8. loosing floor area, because your decorating anyway?
9. Agreed

Why did you edit my original post?

The fact remains - the finish is flimsy (mesh wont stop the plaster cracking if its hit by a sliotar), has limited options (flexi only - you cant go with old style cement dash), and its less efficient than correctly installed interior insulation. Its not on the market long enough to definitively say itll stand the test of time.


External for me is really only an option for the most part on 70's on semi detached standard lego brick estate houses that wont be impacted by the compromised finish. If you have an older red brick, sand and cement dashed finish or intricate exterior house finish then external is either not possible or will have the house looking terrible after its done.

Its a great option in smaller, interior finished houses with little disruption caused. I have had it done on my old house but im currently dryining my new home as it has plenty of space, I don't want to compromise how the house looks from the outside and we are gutting the interior anyway. Don't properly by a professional and all the issues (dew points, cold bridges etc.) can be minimised.

Just my 2c

Ryanciaran

Thanks a lot for your opinions. It's a 4 bedroom bungalow in the country. What I was afraid with the ewi was that the plaster would crack if hit with a sliothar or some thing else. Think it's prob best go with the iwi. Although it will make the rooms smaller.
Is triple glaze much better than double? Is it worth the extra cost?

BryanF

cpoh1 wrote: »

1. Why did you edit my original post?

2. The fact remains - the finish is flimsy (mesh wont stop the plaster cracking if its hit by a sliotar), has limited options (flexi only - you cant go with old style cement dash),
3. and its less efficient than correctly installed interior insulation.
4. Its not on the market long enough to definitively say itll stand the test of time.


5. External for me is really only an option for the most part on 70's on semi detached standard lego brick estate houses that wont be impacted by the compromised finish. If you have an older red brick, sand and cement dashed finish or intricate exterior house finish then external is either not possible or will have the house looking terrible after its done.

6. Its a great option in smaller, interior finished houses with little disruption caused. I have had it done on my old house but im currently dryining my new home as it has plenty of space, I don't want to compromise how the house looks from the outside and we are gutting the interior anyway.

7. Don't properly by a professional and all the issues (dew points, cold bridges etc.) can be minimised.

Just my 2c

1. quoted your post only
2. Don't let your kids repeatedly hit a sliotar of it.
3. You've just repeated your earlier mantra, what efficiency are you referring to???
4. The better companies are around long enough, I explained that in my previous post
5. Red brick - yes I here what your saying , but this is bungalow! It's an ideal candidate for Ewi and the op is changing windows as well! Think about the thermally continuity of Ewi? It far superior when compared to iwi
6. How a bungalow looks. Can only be improved..
7. Can you explain to us what professional your using and how he/she is dealing with due-points at all the linear thermal bridges that will never be solved with drylining ?

BarneyMc

Ryanciaran wrote: »

Thanks a lot for your opinions. It's a 4 bedroom bungalow in the country. What I was afraid with the ewi was that the plaster would crack if hit with a sliothar or some thing else. Think it's prob best go with the iwi. Although it will make the rooms smaller.
Is triple glaze much better than double? Is it worth the extra cost?

When I bought about 2 years ago the difference in price between double and triple was about 12%. Get quotes but a no brainer in my opinion - go for 3G.

cpoh1

BryanF wrote: »

1. quoted your post only
2. Don't let your kids repeatedly hit a sliotar of it.
3. You've just repeated your earlier mantra, what efficiency are you referring to???
4. The better companies are around long enough, I explained that in my previous post
5. Red brick - yes I here what your saying , but this is bungalow! It's an ideal candidate for Ewi and the op is changing windows as well! Think about the thermally continuity of Ewi? It far superior when compared to iwi
6. How a bungalow looks. Can only be improved..
7. Can you explain to us what professional your using and how he/she is dealing with due-points at all the linear thermal bridges that will never be solved with drylining ?

1,2c3,4,5,6 & 7 - sorry don't have time to respond to your nice breakdown of points!

You know well enough where I am coming from with both my original post and subsequent ones, they are all well established drawbacks of EWI

Calahonda52

Ryanciaran wrote: »

Thanks a lot for your opinions. It's a 4 bedroom bungalow in the country. What I was afraid with the ewi was that the plaster would crack if hit with a sliothar or some thing else. Think it's prob best go with the iwi. Although it will make the rooms smaller.
Is triple glaze much better than double? Is it worth the extra cost?

This reasoning is flawed.
The discussion on the finish has been limited to render on mesh on the EWI as it is touted as the only solution for finish, as is aeroboard for the only EWI, which is not the case.

There are other, rigid, finishes available such as cement board that can be used.

A point which has not been addressed here is that u need to bring the EWI up through the soffit board and have it link in with the roof ceiling insulation.
Whats the plan with the roofing felt?

Some where above it was suggested that IWI was better for dew point management than EWI.
That is wrong.

To conclude here, you have once in a life time opportunity to do this right so take heed of what Mick said about the windows mounted externally on the wall first, before the EWI, some years back a bloke here: SAS, posted some pics of how it looks doing it this way: see attached

little_monty

I'm about to have EWI fitted on my ~20 year old bungalow.

Almost all the research I've done, and instinct suggests to me EWI is the best option for me and my house. (mainly because EWI can give a more complete covering of the house than IWI (e.g at internal walls, over the ceilings)

I agree that EWI comes with some risks (as does IWI) which I think can be mitigated by using an established company and closely examining the system they propose. (talk to previous customers of the company you're considering)
All the people I've talked to with EWI were very happy with it but I've heard of people who'd had to get in 2nd company to repair the poor job done initially !

If going with high standard of insulation (EWI or IWI) then I think triple glazing windows + very good attic insulation + good air tightness & ventilation are a no-brainer