Internal insulation - which way should I go - conflicting information

molleman · 24-11-2024 03:55PM #1

Hello guys ,

I don’t know which way to go with internal insulation .

Here is some pictures of the inside of my house.

What are the possible methods I could about insulating my home internally. The floor space is about 45 square meters downstairs . Saving space is a must. EWI is possible but have to wait some time to afford.

There’s a lot of information out there but I don’t know what’s right for me.

The house is built in 1948 and poured concrete.

Few points

I won’t be removing the stairs and they are on an external wall. I have to be careful here with Insulation as they will make the stairs to narrow.

The joists run along the front and back wall and they are basically on the wall with no way to get any insulation between them and the wall.

Any help would be great . Or a point in the right direction .

24-11-2024 04:02PM

Wait until you can go EWI. Seriously. I cant stress that enough. Internal is hard to get right. Cold bridges are hard to eliminate.

molleman · 24-11-2024 04:12PM

Ok thanks for this .

for now what do I on the inside ?

Batton the walls and put plasterboard up?

No insulation at all ?

MicktheMan · 24-11-2024 04:22PM

What's your air tightness plan?

molleman · 24-11-2024 04:38PM

Honestly, I don’t have an airtightness plan. My current focus is more on improving insulation rather than going for full airtightness. I was planning to rely on vents for ventilation since my budget is quite tight, and adding the complexity of airtightness along with a mechanical ventilation system isn’t something I was aiming for right now. I’m trying to balance practicality and cost while still making the house more energy-efficient."

Tippbhoy1 · 24-11-2024 05:05PM

The big question mark for me is the fact you don’t have a double leaf wall. This I believe raises additional concerns around condensation behind the insulation if it’s not sealed right and the complexities that can bring.

That being said, I’d probably vent the space and slab it all up with at least 60mm insulated board. Depending on height of the ceiling I’d do the same there. Worth talking to a professional.

MicktheMan · 24-11-2024 06:45PM

https://www.boards.ie/discussion/comment/122878360#Comment_122878360

I’m trying to balance practicality and cost while still making the house more energy-efficient."

This is my point in our rather temperate but windy climate. Going on the pics above, imo, achieving excellent air tightness shouldn't be too difficult, complex or costly. Now is the time to get this right, you would not be able to do half as good a job later. My advice is to have the house tested for air tightness now to understand the opportunity you have. Btw, trickle / 'hole in wall' and intermittent vents just don't work in our climate.

EWI can always be done at a later stage when funds allow.

Going this route will more or less guarantee you get not only an energy efficient house but also a healthy one with very low risk of moisture / damp issues. I would fear that what you are proposing might well yield the opposite.

Calahonda52 · 24-11-2024 07:39PM

Is that a new floor?

What's the plan with the windows/doors? are they new?

My concern here is if there is a damp proof course in the walls.

My guess is no as I am working on a similar aged home and there is no DPC.

So, IMO, IWI is a no no so wait till you have the mula for the EWI and if windows are on the list don't do them before the ewi but at same time, it gives the best result but not a show stopper.

U asked about PB on battens?

This would act as a service cavity for electric etc

Calahonda52 · 24-11-2024 07:41PM

https://www.boards.ie/discussion/comment/122878480#Comment_122878480

The singe leaf wall would benefit greatly form EWI with rain shield

your suggestion will reduce room size by maybe 150 mm all round because for it to work prolly the studs must stand off the wall

TimHorton · 24-11-2024 08:11PM

https://www.youtube.com/watch?v=Ou1CjwflZtM

10-10-20 · 24-11-2024 09:34PM

I agree with the above - external insulation is best here but I'd advise you to start reading about how to best maximize the insulation in terms of pushing the windows and doors outwards and then applying air-tight tape internally on each junction. This means that you need to be careful with any window or door replacement in the period before installing the external insulation. The massive amount of concrete in the building will then serve as a huge thermal mass and keep the heat level nice and stable.

Also consider DIYing the external insulation and then hiring a plasterer to render the exterior. You can often see all of the methods and instructions on how it needs to be installed online.

This looks like an excellent space and I hope that you have many happy years there.

molleman · 25-11-2024 01:07AM

hi

yes we have 150mm of insualtion in the floor , underfloor pipes and then 60mm of screed .

Windows are 15 years old double glazed .

Yes there is damp proof course in the walls , and a dpm under the floor also.

Yes I just wanted to know what to do on the walls .

Along gable wall I will have to batton , but going up the stairs I can’t batton as it will take up too much space . Do I remove the old plaster there ? And then what to do on the stairs wall ?

Calahonda52 · 25-11-2024 08:36AM

if you ewi 3 walls and iwi the gable, then you will have a big thermal bridge

TimHorton · 25-11-2024 05:10PM

https://www.boards.ie/discussion/comment/122879614#Comment_122879614

Any links to online tutorials for DIY EWI Install?

hesker · 25-11-2024 05:42PM

https://www.boards.ie/discussion/comment/122883054#Comment_122883054

Look up the manufacturer’s website and you will find the technical installation manuals that companies should be following but yet somehow lots of them manage not too.

Loads of videos on YouTube also. One lad in Kerry has an excellent series of fairly detailed vids.

molleman · 25-11-2024 08:44PM

Right, so I’ve decided to go with EWI in the future.

For now, what’s the best way to put plasterboard up on the inside?

Should I go with dot and dab, use battens, or maybe a mix of both?

What are your thoughts?

10-10-20 · 25-11-2024 08:52PM

https://www.boards.ie/discussion/comment/122883965#Comment_122883965

Insulated plasterboard or just plain plasterboard to finish off the surface? As it's concrete I think that battens over a damp-proof membrane is best, others will have better ideas.

hesker · 25-11-2024 10:14PM

https://www.boards.ie/discussion/comment/122884011#Comment_122884011

Why would you suggest that out of interest. OP has said there is a dpc and floors are newly laid.

Given OP is going with EWI why not just plaster the walls.

OP I’m someone who is most of the way through a retrofit in a house similar to yours (single leaf). EWI fitted and I can tell you it has been a complete transformation. House is now very cozy and I still have attic insulation to fit.

With the ceilings removed you have a great opportunity to get a lot of prep work done.

Have a good think about what you want to end up with and think about the long term. If I was you I would assess the following while house is gutted

Rewire
Pipework for future heat pump
Fitting duct work for MVHR
Fitting airtight membrane to ceilings

You can get a lot of grants under OSS for
EWI
MVHR
Windows and doors
Heat pump

It will still cost a small fortune.

We internally insulated one living room and lived away in that for several years before we had enough money to finance it all.

Worth talking to a OSS to check what work you can do up front and what you can’t. You can install air tightness membranes for example as currently there are no grants for that. I’m not sure if installing duct work now would prevent you applying for MVHR grant in future.

Best of luck

10-10-20 · 25-11-2024 10:24PM

https://www.boards.ie/discussion/comment/122884371#Comment_122884371

"Why would you suggest that out of interest. OP has said there is a dpc and floors are newly laid.Given OP is going with EWI why not just plaster the walls."

He appears to be looking for an interim solution and as it's mass concrete then there would be concerns around penetrating damp over this interim period, so it's critical that there be a vapour barrier included in the build-up of the wall.

hesker · 26-11-2024 01:02AM

I’ve heard on here that gypsum plaster offers a very good vapour barrier though I’m pretty sure it’s not impermeable to liquid water which is essentially what damp is. Protection against penetrating damp would be provided by external render which might already be intact but possibly in need of repair, and the dpc already mentioned.

standardg60 · 26-11-2024 08:05PM

https://www.boards.ie/discussion/comment/122883965#Comment_122883965

As C52 mentioned above battens would give you a rat run for an electric circuit as I don't see any sockets on the fireplace wall so factor that in. 40mm or even 25mm battens with rigid insulation between would at least get you started on insulating the walls.

If you're happy the wall has been properly rendered outside and bone dry I wouldn't see the need for DPM but again others may advise on that.

Internal insulation - which way should I go - conflicting information

Comments