Render External Insulation Finish v Internal Dry Line

Noggle

I've a quote for an indicative price to insulate my 3 bed detached ( S. Co.Wicklow),

120mm of Spray foam insulation throughout roof. 1
Opening up trace and access works and patch and repair works
to ceilings.

Supply and fit 80mm insulated plasterboard on all exterior walls
and skim.


I prefer the idea of the external.

Could I get the roof done as one contract and the walls as a separate one?

How much are the SEAI grants for this work.


Any other advice.

I'm aware that draught proofing and windows are important components also.

Calahonda52

need to know more about the exact makeup of the external walls as well as the type of felt used in the roof

listermint

The quote should have included the seai grant..did you not ask the contractor ?


Also 80 mm is quite small.

Noggle

listermint wrote: »

The quote should have included the seai grant..did you not ask the contractor ?


Also 80 mm is quite small.

He's handling th grant the cost to me is net. of grant amount he says 80mm is standard?

What do you think of the external job?

listermint

Noggle wrote: »

He's handling th grant the cost to me is net. of grant amount he says 80mm is standard?

What do you think of the external job?

100 mm would be average. I wouldn't want to go below that.

Calahonda52

Noggle wrote: »

He's handling th grant the cost to me is net. of grant amount he says 80mm is standard?

What do you think of the external job?

OP, you need to be crystal on what you are speaking about here:

Is this what you mean by external job:
Supply and fit 80mm insulated plasterboard on all exterior walls
and skim.

If so then that is internal wall insulation and not EWI

Noggle

Calahonda52 wrote: »

OP, you need to be crystal on what you are speaking about here:

Is this what you mean by external job:
Supply and fit 80mm insulated plasterboard on all exterior walls
and skim.

If so then that is internal wall insulation and not EWI

Thanks, I was a little unclear at the start before I began looking into it,of course you are correct. What it boils down to is whether the internal dry lining or the external wall insulation is superior . I'm beginning to think the external wall insulation is better, the energia website seems to imply that.

Alkers

It's also much more expensive though

mick121

Noggle wrote:

Thanks, I was a little unclear at the start before I began looking into it,of course you are correct. What it boils down to is whether the internal dry lining or the external wall insulation is superior . I'm beginning to think the external wall insulation is better, the energia website seems to imply that.

External is the way to go.it's expensive but you will notice a huge difference.I got it done about 8 years ago.Can't fault it and haven't needed to paint the outside of the house since.

Noggle

mick121 wrote: »

External is the way to go.it's expensive but you will notice a huge difference.I got it done about 8 years ago.Can't fault it and haven't needed to paint the outside of the house since.

Here's what a guy said to me


THE main advantages of External Wall Insulation over Internal Wall Insulation are the following



· External means you wont be losing room space inside

· You wont need to redecorate inside the house

· External eliminates all cold bridging

· House is re-rendered giving it a fresh new build build look

· Larger Grant available



That's fairly short on technical info. I'm still struggling to understand why the External is much better and why it's WORTH the money.

Lumen

Noggle wrote: »

I'm still struggling to understand why the External is much better and why it's WORTH the money.

You just listed a load of reasons. Which of those is unclear?

Think of it this way. Your walls are maybe 3m per storey on the outside and 2.4m per storey on the inside. How does your proposed internal insulation solution deal with that 20% gap?

mick121

Noggle wrote:

· External means you wont be losing room space inside

Noggle wrote:

· You wont need to redecorate inside the house

As well as this there is the issue of removing/replacing skirting and maybe some architrave, the added mess of plastering. With external,all mess is kept outside.

whizbang

Just remember with External, the tops of the walls are not covered. Essentially this means any heat getting into the walls is escaping out the top. If you have any sort of cavity in the walls, this becomes a major issue.

Attic/ roof insulation must be managed to coincide with wall insulation. Better off getting one contractor.

Really all depends on makeup of walls, roof, internal structure. Gable ends ?


Added bonus of External is improved waterproofing.

gctest50

Noggle wrote: »

Here's what a guy said to me


THE main advantages of External Wall Insulation over Internal Wall Insulation are the following



· External means you wont be losing room space inside

What do you live in ? a dog kennel ? you won't miss it

Noggle wrote: »

· You wont need to redecorate inside the house

Might need to be painted anyway

Noggle wrote: »

· External eliminates all cold bridging

The heat will bleed through the tops and bottoms of the walls

Noggle wrote: »

· House is re-rendered giving it a fresh new build build look

Looks weird

Noggle wrote: »

· Larger Grant available

A larger grant ? the price of the job goes up

Muahahaha

gctest50 wrote: »

What do you live in ? a dog kennel ? you won't miss it

Just on that point internal insulation seems to be recommened at 100mm. While losing that space might not sound like much it depends on where you lose it. In my own case the stairs go up the gable end of a semi D. A contractor said they would only be able to fit 60mm of dry lining to the inside of the gable wall because any more and the stairs would be too narrow for building regs. So if I were to go with internal dry lining the main weather side of the house would only be getting 60mm of insulation compared to 100mm for the rest. Im no insulation expert but insulating the part of the house that gets a lot of wind and rain with only 60mm sounds like it could be a botch job. Its a good enough reason to look at external over internal imo.

Problem with external is the price really, it is about 40% more expensive compared to internal. I can see why people go for internal for price reasons alone, especially if they are also upgrading windows and doors at the same time. I wonder is there any scope for external insulation to come down in price over time or is the current pricing as good as its going to get?

whizbang

100mm seems way overkill for internal. Thats the recommendation for new build cavity.

The increased insulation value for 100mm over 60mm is way less than the increase in cost (and space).

But the devil is in the detail as usual. Well fitted 40mm through the floor ceiling levels is way better than badly fitted 100mm

Only 40% ? maybe external is getting cheaper, but sounds odd.

Noggle

For a proper installation with minimum thermal bridging, windows should be unfixed and moved to the outside line of the original wall, drainpipes should also be moved out, roof eave fascias need adapting and any concrete paving surrounding the house should be cut back to ensure the insulation clads the full height of the relevant external walls

http://www.buildinglifeconsultancy.com/architecture/cost-perspective-internal-vs-external-insulation

So there’s also the cost of moving all external fixtures . Also I’m concerned about heat bleeding out thru tops and bottoms of walls, particularly bottoms as I’m getting attic done also.

Noggle

https://www.thegreenage.co.uk/external-wall-insulation-versus-internal-wall-insulation/

enfant terrible

Noggle wrote: »

http://www.buildinglifeconsultancy.com/architecture/cost-perspective-internal-vs-external-insulation

So there’s also the cost of moving all external fixtures . Also I’m concerned about heat bleeding out thru tops and bottoms of walls, particularly bottoms as I’m getting attic done also.

Would the contractor installing the external insulation carry out moving the windows? etc

Or would you need a separate contractor for all those issues?

Noggle

enfant terrible wrote: »

Would the contractor installing the external insulation carry out moving the windows? etc

Or would you need a separate contractor for all those issues?

I don’t know, I’m assuming that’s included in the contract and the price,but you know what they say about assuming