Old house refurb insulation advice please

MAJJ

Hi Folks,

Have a house built in 60s that needs refurb and an approx 17 sqm extension.

In tandem with insulation we are replacing glazing with double glazing in existing house and treble glazing in extension. Also, putting in new gas boiler, rads and zoned heating and controls.

It's 5 bed semi d joined to neighbours via a garage. Two of the bedrooms are over the garage concrete slab.

We intend on internally insulating all external walls
Floor insulation on the wooden floor boards. Ceiling height is 9 feet in the rooms.
Insulation above/below the concrete slab to ensure bedrooms are comfortable.
We intend on insulating the attic with 6 inch fibre and will floor some being clareful not to compress the insulation


Looking for insulation advice on products, thickness needed. Not aiming for a particular BER rating or spec but want to improve efficiency all round.

Thanks in advance for any help,
MAJJ

MicktheMan

MAJJ wrote: »

Hi Folks,


1. we are replacing glazing with double glazing in existing house and treble glazing in extension.
2. We intend on internally insulating all external walls
3. Floor insulation on the wooden floor boards. Ceiling height is 9 feet in the rooms.
4. Insulation above/below the concrete slab to ensure bedrooms are comfortable.

1. why 2 type
2. what's the current wall makeup?
3. ?? no idea what you mean here.
4. why above & below

What are you doing about airtightness and ventilation?

MAJJ

MicktheMan wrote: »

1. why 2 type
2. what's the current wall makeup?
3. ?? no idea what you mean here.
4. why above & below

What are you doing about airtightness and ventilation?

Hi Mick,

thanks for taking the time to respond, it's much appreciated. A lot of my rational is coming from likely poor high level knowledge so am very open to ideas but we are very constrained with costs and many quotes so far are way above expectations.

2. Current wall I believe is 9" hollow block, Dublin built 1960s.
1. Because of the belief that there's little point in putting triple glaze in the existing house but would benefit more in the new extension.
3. The ground floor is a suspended wooden floor, I want to insulate this. I mentioned ceiling height as I thought I may be able to lay a rigid insulation over the floor boards.
4. Bedrooms above concrete slab over unheated garage, I want insulate - not sure if is should be above or below concrete

I am glad you mentioned airtightness and ventilation.
Airtightness - even more out of depth here, am aware or taping than can be used during window install. Maybe on insulated boards? Am open for any info. or guides here.

Ventilation - right now little to no vents in house, so was planning on cutting new vents in block with basic covers. Likely blasphemy and same approach used for decades.

Thanks and go easy on me
MAJJ

MicktheMan

If costs are that constrained, I would advise not to do a lot badly but rather do a little well and do the rest well when the funds are available.
By this I mean, concentrate on those elements that cannot be done in the future when more funds are available. For example, your suspended timber floor is more than likely leaking air like a sieve, so I would lift the boards and not only insulate but also air tighten the floor. You then refit your boards and you still have your full room height.
Similarly with the walls, I wouldn't recommend internally insulating (google "breaking the mould" by Joseph Little) but wait and get external insulation done in the future.
There is little difference in cost between double and triple glazing so go triple on all windows...but make sure the new frames are airtightened properly to the walls. (These windows can then be moved out later and wrapped in your external insulation).
Research other methods of ventilation other than "hole in the wall".
Not knowing the exact makeup of the garage and room above its difficult to advise but generally insulate from beneath I would think.

Note; all of the above is based on a lot of assumptions on my part and could be completely inaccurate. So you should really have the house tested / surveyed by an experienced professional who can advise you based on fact and not guesswork.

dathi

MAJJ wrote: »

Hi Folks,


We intend on insulating the attic with 6 inch fibre and will floor some being clareful not to compress the insulate
MAJJ

6 inch or 150mm fibre is not enough insulation in your attic should be 300mm minimum

MAJJ

MicktheMan wrote: »

If costs are that constrained, I would advise not to do a lot badly but rather do a little well and do the rest well when the funds are available.
By this I mean, concentrate on those elements that cannot be done in the future when more funds are available. For example, your suspended timber floor is more than likely leaking air like a sieve, so I would lift the boards and not only insulate but also air tighten the floor. You then refit your boards and you still have your full room height.
Similarly with the walls, I wouldn't recommend internally insulating (google "breaking the mould" by Joseph Little) but wait and get external insulation done in the future.
There is little difference in cost between double and triple glazing so go triple on all windows...but make sure the new frames are airtightened properly to the walls. (These windows can then be moved out later and wrapped in your external insulation).
Research other methods of ventilation other than "hole in the wall".
Not knowing the exact makeup of the garage and room above its difficult to advise but generally insulate from beneath I would think.

Note; all of the above is based on a lot of assumptions on my part and could be completely inaccurate. So you should really have the house tested / surveyed by an experienced professional who can advise you based on fact and not guesswork.

Thanks Mick, I agree with the idea of doing less but do it right - we're rethinking.

Any pointers on how to approach the insulation and airtightness of the suspended timber floor from a materials and process point of view. Have read a lot of conflicting advice about airflow/damp and a bit puzzled on how to even approach that job.

Read that article and found it very interesting I get the high level principle. Our house would also benefit from external insulation as it would visually upgrade it too. We could only do this at the front and rear but not the side as we are joined at a garage to our neighbours and our extension above the garage goes straight up to a parapet/valley. Basically that "gable" we can't externally insulate. I assume this would cause us cold bridging and I assume that we would also need some kind of internal insulation overlapping to deal with this.

You mention a suitable professional - what type please ? An architect? If so, we have one but not going too well.

Thanks for any advice you or others can give,
MAJJ

MicktheMan

Google NSAI S.R.54 and have a read.

The professional I was alluding to is not an architect but rather somebody to actually test your house and based on the results, advise on the most appropriate improvements.

BoardsMember

Re the suspended timber floor, I am absolutely not an expert, but I need to get it done too so have been keeping an eye open as to how best to do this, as we live with very draughty floor boards.

Here's what we plan to do:

- lift the boards
- fit breathable hardboard insulation between the joists, leaving room for air movement
- ideally use tape to try to seal from underneath, though I am not sure how much room there is to work in that space

I'm not sure how else it can be done and it sounds like a really messy job, but if you're in an old house with floor boards, it's a starting point for getting things snug in the colder months

MicktheMan

BoardsMember wrote: »

Re the suspended timber floor, I am absolutely not an expert, but I need to get it done too so have been keeping an eye open as to how best to do this, as we live with very draughty floor boards.

Here's what we plan to do:

- lift the boards
- fit breathable hardboard insulation between the joists, leaving room for air movement
- ideally use tape to try to seal from underneath, though I am not sure how much room there is to work in that space

I'm not sure how else it can be done and it sounds like a really messy job, but if you're in an old house with floor boards, it's a starting point for getting things snug in the colder months

Best to seek expert professional advise and not guess at it and hope for the best. If you watched the "room to improve" programme on rte last night, it shows the consequences of getting detail like this wrong.
What do you mean by "breathable hardboard insulation"

BryanF

BoardsMember wrote: »

Re the suspended timber floor, I am absolutely not an expert, but I need to get it done too so have been keeping an eye open as to how best to do this, as we live with very draughty floor boards.

Here's what we plan to do:

- lift the boards
- fit breathable hardboard insulation between the joists, leaving room for air movement
- ideally use tape to try to seal from underneath, though I am not sure how much room there is to work in that space

I'm not sure how else it can be done and it sounds like a really messy job, but if you're in an old house with floor boards, it's a starting point for getting things snug in the colder months

http://www.boards.ie/vbulletin/showpost.php?p=97719951&postcount=3

BoardsMember

BryanF wrote: »

http://www.boards.ie/vbulletin/showpost.php?p=97719951&postcount=3

Thanks. What type of insulation? What to use as air tightness layer? I'll be taking professional advice when I go to do it, just interested. Is the purpose of the felt to catch/hold the insulation l?

BryanF

BoardsMember wrote: »

Thanks. What type of insulation? What to use as air tightness layer? I'll be taking professional advice when I go to do it, just interested. Is the purpose of the felt to catch/hold the insulation l?

Recycled plastic bottles
intello. 2 tapes, one for concrete/plaster behind skirting & one for membrane to membrane.
Cheapest Breathable roofing membrane available to minimise air-movement through insulation.

start thinking about whether you want to keep the floor boards and how your going to get them up..

BoardsMember

BryanF wrote: »

Recycled plastic bottles
intello. 2 tapes, one for concrete/plaster behind skirting & one for membrane to membrane.
Cheapest Breathable roofing membrane available to minimise air-movement through insulation.

start thinking about whether you want to keep the floor boards and how your going to get them up..

We would want to keep the floorboards alright, we'd hope the builder might have suggestions how to get them up. They are the original boards, 1920's house.

BryanF

BoardsMember wrote: »

We would want to keep the floorboards alright, we'd hope the builder might have suggestions how to get them up. They are the original boards, 1920's house.

Builder will want to get rid of them. Expect increased price & caveats of quality to keep. Best to seek good finishing carpenter with references - and expect that he will have to take his time with probably 30% breakage minimum.