Insulating Attic From Scratch

Hi all:

Prior to getting treatment for woodworm, I had to remove all insulation from the attic, so its now back to the plaster board with wiring exposed.

1970's build. Standard spacing between joists.

I'm not sure what products to use or varying methods to re-insulate attic.

But due to limited budget, I think it will have to be standard loft roll insulation.

(Polystyrene foam filled insulation has been mentioned to me but its out of my budget at present and I'm not sure exactly what that entails or even if its possible with the build of the house).

Any basic ideas or suggestions appreciated. Eg, depth of insulation needed.

(Boy the house is freezing at the moment!)

Thanks

Calahonda52

Can you describe, in detail please,
the eaves construction: e.g.

1. is soffit ventilated?
2. is there concrete between the rafters over the wall plate?
3. what material is roof felt?
4. is there an insulated Cold water tank?
5. Is attic attic airtight and insulated?
6. are there down lighters?
7. Anything else occur?

This attachment should help: its 200 odd pages, c 13 Mb
https://www.nsai.ie/S-R-54-2014-Code-of-Practice.aspx

Hi Calahonda:

A few quick responses and thanks for your post.

I'm pretty clueless about construction but I'll try me best as I see it.

1) Soffit ventilated: The air is flowing freely from outside under the eaves. in some places day light can be seen.

2)Concrete between the rafters over the wall plate? (This is the tiny space at the end of the joist?) There seems to be some concrete, although I thought this was just concrete left over from building? I haven't checked to see if occurs in all places. I can check that later.

3) What material is roof felt? On the underside of the roof is a this black/tar type covered lining. Coming away in places (4 or 5 places) with the wind coming in. (It was mentioned to me that this is no bad thing for ventilation).

Nothing else between that and the roof tiles.

4) Is there an insulated Cold water tank? No, cold tank not insulated. Original 1970's job.

5) Is attic attic airtight and insulated? No quite sure what you mean here. Is that gaps between pipes and loft cover etc?

6) Are there down lighters? Not sure what these are, but No nothing else installed in attic.

7) Anything else occur? House has no cavity in wall.


Thanks for the attachment also.. many thanks.

PS: 6) No downlights. Just electrical wiring that goes through plaster board to light fitting on ceiling below.

Calahonda52

thanks, meant attic hatch

I will try post a picture of the concert between the rafters over the wall plate.
The issue is that if it is there then, if the soffits are ventilated, the air can't pass up between the felt and the concrete so this detail is important
look at page 66, plus and minus in the attachment for the detail showing eaves carriers.

The torn felt might be a bonus for ventilation but if rain gets in under the roofing material then .....drip drip drip....
What is roof covering, concert tiles or slates.
Re the final insulation solution, we will get to that, however IMO the rolled insulation you mention is not the right answer, we will get to why later.
You will be looking at maybe, in total 400mm of insulation, with the power cables being sleeved in ducts so as they don't overheat.
the ducts are flexible and will need to be split along the side to allow fitting, without cutting the cables, which is certainly frowned upon if not even forbidden under the elec regs
In passing is the roof gabled at each end or have you two hips?
is the house attached or semi D or terraced or..?

Thanks so much for your advice, much appreciated.

Rood covering is concert tiles.

We have one gable end. Semi-d house open gable.

Have to head out now for a few hours. Thanks so much for your time and advice.

One other item, on the underside of the plaster board, at the gable end of the house, condensation mould has gathered on the ceiling, below where the plaster boards are. There is no condensation beneath where the joists are. Just about 3 inches from the wall.

When I put in roll insulation a few years ago, on top of the original flattened insulation, i stuffed it right up under the eaves, but was concerned about the air flow and then removed it all, and possibly the original insulation too, leaving only the plaster board.

Sleeper12

Kyree Juicy Truck wrote:

4) Is there an insulated Cold water tank? No, cold tank not insulated. Original 1970's job.

I'd get rid of this ASAP. Galvanised tanks rot from the inside out. Your insurance will cover galvanised tanks up to 10 years old. Any leaks or burst tanks older than that and they don't pay out for. Well worth investing in a plastic tank with a lid and properly supported. If on a budget personally I'd do the tank first as a damaged rank will cost you more than you'll save in years with the insulation

@Sleeper12

@Sleeper12.

Thanks for that good to know. However, I must have given wrong info/impression by saying "70's".

It is a plastic tank, but its a good age, and is well supported from what I can see. Thanks again.

wait4me

Just hopping into this thread as its dealing with insulation. Early 1990's house with loft insulation already in place. Any benefit in rolling out extra insulation over the stuff that is there at the moment. I presume the thermal benefits of the old stuff will eventually diminish; and I'm able to get into the attic nowadays. 10 years into the future I may not be able to get the creaky bones up there.

Sleeper12

Kyree Juicy Truck wrote:

It is a plastic tank, but its a good age, and is well supported from what I can see. Thanks again.

Plastic is perfect.

Sleeper12

wait4me wrote:

Just hopping into this thread as its dealing with insulation. Early 1990's house with loft insulation already in place. Any benefit in rolling out extra insulation over the stuff that is there at the moment. I presume the thermal benefits of the old stuff will eventually diminish; and I'm able to get into the attic nowadays. 10 years into the future I may not be able to get the creaky bones up there.

You'll get great advice on the sei website. You'll get conflicting views here. I would suggest yes. More insulation, quilting it. Always make sure that large cables, shower cables for example, are on top of the insulation so they don't over heat

wait4me

wait4me wrote: »

Just hopping into this thread as its dealing with insulation. Early 1990's house with loft insulation already in place. Any benefit in rolling out extra insulation over the stuff that is there at the moment. I presume the thermal benefits of the old stuff will eventually diminish; and I'm able to get into the attic nowadays. 10 years into the future I may not be able to get the creaky bones up there.

When I did the re-insulation about 5 years ago, I put the new insulation down over the old stuff which was very flat. Putting new stuff down was easy enough, just the hassle of working in cramped conditions.

Removing all the insulation over the weekend was a much bigger, horrible job. The insulation expands and is much harder to bag up. About 50 plus bags of the stuff. And then getting it disposed of.

I'm no expert at all, but I'd like to think its best to leave the old stuff where it is and lay over the top of it. Saves a lot of hard work and itchyness.

Overalls, mask and protective glasses the order of the day.

Calahonda52

wait4me wrote: »

Just hopping into this thread as its dealing with insulation. Early 1990's house with loft insulation already in place. Any benefit in rolling out extra insulation over the stuff that is there at the moment. I presume the thermal benefits of the old stuff will eventually diminish; and I'm able to get into the attic nowadays. 10 years into the future I may not be able to get the creaky bones up there.

Answer all the questions in my posts to the OP as they pertain to your gaff, download the document, look at pages 66 plus and minus and then we will comment

Water John

wait, be very careful with old insulation. As some other poster said, mask and goggles. Know someone who did serious damage to their lungs.

whizbang

The main issues for the OP is the drafts, and possibility of damp in the insulation.

Any Glassfibre/earthwool type stuff is almost useless in this situation.
And it may be a lot easier to use rigid type insulation.

BTW is the ceiling plasterboard foil backed?

whizbang

whizbang wrote: »

The main issues for the OP is the drafts, and possibility of damp in the insulation.

Any Glassfibre/earthwool type stuff is almost useless in this situation.
And it may be a lot easier to use rigid type insulation.

BTW is the ceiling plasterboard foil backed?

Thanks for that. The plasterboard isn't foil backed. I had an engineer inspect and the attic is dry.

Calahonda52

whizbang wrote: »

The main issues for the OP is the drafts, and possibility of damp in the insulation.

Any Glassfibre/earthwool type stuff is almost useless in this situation.
And it may be a lot easier to use rigid type insulation.

That is largely inaccurate, based on the science and what the OP has stated

What is the best way/what product is best used to put back into place waterproof membrane under roof tiles?

It has come away in a few places. Its not ripped, it just seems to have been blown-in in a few places from under the rafter.

Flashbanding?

Calahonda52

If its close to the eaves and you have a hip roof and you want to do the insulation properly at the wall plate, it is best to strip off maybe the first meter or so of roof tiles up from the gutter and redo the felt after the insulation is done as per page 66 +/- in the book

Calahonda52

Calahonda52 wrote: »

If its close to the eaves and you have a hip roof and you want to do the insulation properly at the wall plate, it is best to strip off maybe the first meter or so of roof tiles up from the gutter and redo the felt after the insulation is done as per page 66 +/- in the book

Yes that would be the best job. One for a roofer though, I'll speak with one of the lads. Thanks.

Calahonda52

You should replace the felt you remove with breathable felt: e.g. tyvek is the hoover brand of roofing felts.
The roofer may do the roofing bit but somebody who knows what they are about is required for the insulation project