Old house - Internal Insulation

Boscod

I need to do a short term fix (5 years or so) on an old stone built cottage I have. The place currently has no insulation whatsoever and indeed smells of damp. I'm planning to do a more extensive and propper renovation at some later point, so need to keep these short-term costs at a minimum.
I am planning to strip all wall coverings, fixing a damp proof membrame with battons followed by a 38mm insulated slap to all external walls.
Any thoughts on this approach or is there any simplier/more effective solutions?

Thanks for your feedback.

TopTec

Where to start?

You want what can't be had. There is no 'short term fix' for insulating an old place.

Your first job is to fix any damp problems. This can be mostly achieved by ventilation and dealing with gutters, downpipes, loose slates, chimney flashing, built up debris against walls, leaking valleys etc, etc.

The ventilation is essential as you want to create an airflow through the cottage, wicking away the moisture using vents in walls and windows.

This can take months and sometimes years depending on the construction of your walls and roof.

A damp proof membrane where? Presumably under the floor?

Wall and loft insulation has no cheap alternative. If you are going to fork out for insulated wall slabs then they should last decades so do it right the first time.

I have an old 18th century cottage and am 3 years into a refurb and now have a dry warm cottage following these guidelines.

TT

1930sRevamp

Hi Guys,

I'm new here. Just starting renovation of a 1930s solid cement structured two-storey - 4 up, 4 down. We're doing internal dry-lining and the builder is trying to persuade us not to apply for the SEAI grant, as we'll be forced to have higher insulation than is necessary. He says the SEAI requirements for insulation are too high, to leave the house breathable and comfortable to live in. I think he's suggesting 50mm rather than 90mm that is required under SEAI? For us, I'd prefer scrimp on the kitchen or those things, rather than on insulation as want it done right, only once.

Any advice would be greatly appreciated.

TopTec

What is the grant now, 2 grand?

I am not an expert but the more insulation the better up to a level where it makes no difference. I would say 90mm is better than 50mm. I have 90 mm in my bathroom but have 50 mm in my other rooms. The bathroom was the coldest room and has 2 external walls where the others only have one. How much over the grant will you be paying for 90 mm compared to the 50mm? Breathability and comfort are crap excuses in my opinion.

Put on the best you can afford and don't forget the loft.

The issue for me was the 6 months deadline for the SEAI grant and I am 3 years into my refurb!!

TT

1930sRevamp

Thanks TT :cool:

The grant is 1800 including attic. The builder is saying we'll end up paying 1800 extra for the wall insulation, so seems like we're breaking even on it. Builder has to pay 1500 to get re-registered on the SEAI list - but he told me that upfront, and I trust him on his advice on other things, so just wondering it there anything in it, that 90mm is too much, or getting to the stage where costs increase rewards.

antiskeptic

1930sRevamp wrote: »

Thanks TT :cool:

The grant is 1800 including attic. The builder is saying we'll end up paying 1800 extra for the wall insulation, so seems like we're breaking even on it. Builder has to pay 1500 to get re-registered on the SEAI list - but he told me that upfront, and I trust him on his advice on other things, so just wondering it there anything in it, that 90mm is too much, or getting to the stage where costs increase rewards.

I did my mothers large living room with 80mm on the vaulted ceiling (single storey house) and 50mm on the walls (two mass concrete external and two mass concrete internal) and the place is toast. I took care to ensure the two windows were draughtproofed (only one is double glazed) too.

There's a case to be made for retaining an amount of thermal mass in your house (the idea being that it will store and slowly release energy and so smoothen out temperature variation). In theory.

In practice, solid internal walls compete for the heat you want to be heating your house right now. And leak that heat back to earth continuously. And give back your precious heat during the night when you're cosy in bed and are in no need of it - by the time you get up, the paid back heat has leaked away through the myriad of ways heat leaks out of your typical house.

1930sRevamp

Antiskeptic,

For your Mum's house, you seem to be saying you put 50mm on both the internal and external mass concrete walls. We're being advised to just put foiled backed plasterboard on internal mass concrete walls, but I take it from above, that you wouldn't agree?

Also, we're battening the insulation onto the solid masonry walls, and I'd like to go 72.5 (60mm insulation & 12.5 plaster board) but the space it takes up is a huge factor to consider. I've read in various places, mostly kingspan & other insulation company's websites, that its also possible to put additional insulation between the battons, against solid masonry. My builder is saying that this insulation, even with damp proof coursing, could get damp, and that a gap needs to be left between solid masonry and insulation boards. What's your opinion on this, having considered it all before?? I'm considering 30mm of Knauff rockwool & 62.5 (including 12.5 plasterboard) on battons - builder thinks the 30mm rockwool is money down the tubes.

Is there any documents or websites anyone can refer me to, to read up a bit more on it? The 04/03/13 Code of Practice on retrofitting, that BryanF referred me to earlier glazes over this point, and doesn't say one way or the other which should be done.

Any advice would be gladly received

seanin98

Can anyone who has used the internal insulation grant let me know how strict they are on inspecting the work. It's just that when we done the attic it was cheaper to do what the builder deemed adequate that what was stipulated for the grant.

The back of our house is south facing so usually pretty warm. We were just going to go for insulated slabs on the front and one side. Is this enough to get the grant or do we have to do all external walls. It's a bungalow.

TopTec

As I recall you can't just do a couple of rooms or walls when applying for the grant. It is designed to insulate your house/cottage reducing your energy consumption.

I don't think partial partial insulation qualifies. I stand to be corrected though it was 14 months ago I last checked their website which is where you would get a definitive answer.

As for your first question are you saying the builder decided to put a lessor level of insulation because he thought it was enough? Wouldn't that reduce the level of grant you qualify for? As for inspection I can't answer for that but your builder would risk losing his accreditation if his work was substandard.

TT

JosephKavanagh

Howdy!

Im looking for some advice here also. I have a 1960's bungalow with masonry walls it has been dorment for the past 9 years... I want to stick the insulated slab internally but Im afraid of condensation forming. what is the correct method?

A. Batton the walls place vabour barrier on it and then insulated slab?

B. fix vapour barrier behind insulated slab and fix directly to the wall?

C. none of the above?

Thanks Joe

MicktheMan

C

JosephKavanagh

Ok thanks... So what is the correct method to install insulated slabs on a masonry wall?

MicktheMan

I can't advise without a lot more information, but, in general, the air /vapour barrier should be on the warm side of the insulation.