An insulation challenge of a 1955 Bungalow!

[uktricky]

OK temperatures have dropped and therefore reminded me that I should have improved insulation in house last year!!!

1955 Bungalow with a Lounge built over a garage and an open stair case leading up to a roof conversion bedroom. The bedroom has a radiator within but an area (landing) outside the bedroom door approx 3m x 2m has no form of heating.

Garage is large but a single with up and over garage door (with lots of drafts) and a concrete roof/floor. Should note that the boiler is located in the garage. Lounge is 3m x 7m with 2 large windows and 2 smaller windows built over the garage. There is NO insulation on the garage roof or between the roof and the joists to floor boards. The space between the two is approx 4" to the under side of the joists which I can see down from under the crawl space under the house. I therefore cannot access easily the space under the lounge.

Crawl space access within Garage (again with drafts) and a door approx 1m square. Leads to rest of crawl space which varies in height under the joist from ~1.5m to < 0.25m

Kitchen is incredibly drafty around non-fixed applianced (washer & dryer) and has a tiled floor. I can access the crawl space under the whole kitchen and the majority of the rest of the house.

I want to improve heat loss from flooring area especially in the lounge and kitchen as these seem to be the rooms which suffer badly for being cold.

Challenge 1 - Under the kitchen (3m x 4m) I have considered putting insulated boards (celotex??) between the joints but not up against the underside of the floorboards (is this OK to do?) and also perhaps under other areas without carpet I.e. Bathroom Floor (Varnished floorboards 3mx4m) and Hallway (Solid wooden floor over original floorboards 1.5m x 8m).

Challenge 2 - The lounge (carpeted) How can I improve the insulation of this floor given the challenge of the space between Garage roof and Joists. Considered trying to push rolls of fibre insulation down using rods but this would be rested on top of the concrete garage roof. Like wise considered Celotex type boards cut into strips to get through access space! again rested on garage roof. Would this be "acceptable" and likely to improve heat loss?

Also considering the replacement of the up and over garage door with a double glazed type unit to reduce the amount of draft as I don't use the garage for vehicles.

Any recommendations given the information above?

 

[AronSearle]

between the joints but not up against the underside of the floorboards (is this OK to do?)

It depends on how drafty the underfloor is, if air can move between the insulation and the underside of the floorboard, to outside spaces, it may greatly reduce the effectiveness of the insulation.

As to insulating under your lounge, being a bit slow, but I can't visualize your house, are the joist suspended over a ventilated air space?

 

[maltaron]

I cannot understand why people are so concerned with floor insulation (other than building regulation experts who are good at spending other peoples money). Heat rises(simple physics). If floors are boarded then draught proofing is all that is required. Tiles, carpets etc will achieve this, and a carpet with a good underlay will provide insulation. I would suggest that if your loft conversion and over garage building are cold then there is a lack of insulation over the top.

 

[AronSearle]

Sorry maltaron, it's not the 1970s anymore, plenty of studies have been conducted on this, you can lose 10-20% of your heat through floors.

Heat rises(simple physics)

Second law of thermodynamics - heat moves to cold areas.

and a carpet with a good underlay will provide insulation

Thanks, I'll remember this next time I'm insulating a loft area.

 

[geraldthehamster]

Yes, Celotex-Kingspan between the joists is effective. Getting it there is the issue. I bit the bullet in my sitting room and took up the floorboards. Cut Celotex slightly undersize for the joists, fixed temporarily then squirted expanding foam to seal it to the joists.

It's important that no draughts can get into the space, if any, between Celotex and floorboards, or this defeats the object. Conversely it's important to maintain underfloor ventilation beneath the insulation.

Taking up the floor might be easier said than done in a fitted kitchen ...

I considered all kind of impractical schemes to avoid taking up the floor (there was no adequate crawl space). In the end I bit the bullet and I'm glad I did it.

Cheers
Richard

 

[pinenot]

Picking up on some points mentioned so far, heat loss is a factor in house floors however drafts from this area are far more prevalent in the fight for sitting comfort. Door bottoms, gaps at skirting boards and between flooring joints can be rectified more easily than adding insulation between existing floored joists, especially in your situation I would think...pinenot

 

[uktricky]

Yes, Celotex-Kingspan between the joists is effective. Getting it there is the issue. I bit the bullet in my sitting room and took up the floorboards. Cut Celotex slightly undersize for the joists, fixed temporarily then squirted expanding foam to seal it to the joists.

It's important that no draughts can get into the space, if any, between Celotex and floorboards, or this defeats the object. Conversely it's important to maintain underfloor ventilation beneath the insulation.

Taking up the floor might be easier said than done in a fitted kitchen ...

I considered all kind of impractical schemes to avoid taking up the floor (there was no adequate crawl space). In the end I bit the bullet and I'm glad I did it.

Cheers
Richard

So place the Celotex right up against the floorboards is best? I was expecting that I should have some kind of Air Gap??? Getting it under there is not an issue really as I have a reasonable access area providing I've cut the strips down first

 

[uktricky]

between the joints but not up against the underside of the floorboards (is this OK to do?)

It depends on how drafty the underfloor is, if air can move between the insulation and the underside of the floorboard, to outside spaces, it may greatly reduce the effectiveness of the insulation.

As to insulating under your lounge, being a bit slow, but I can't visualize your house, are the joist suspended over a ventilated air space?

Very drafty which is down to a poor fitting garage door which I am looking to replace/improve … For visualisation - Imagine a Cake:
Lounge (with a loft area inaccessible above - Need to make access to check insulation)
Lounge Carpet with decent underlay
Floor boards
Joints
about 6 inch of air space
Concrete Garage Roof
Garage Floor

 

[geraldthehamster]

So place the Celotex right up against the floorboards is best? I was expecting that I should have some kind of Air Gap??? Getting it under there is not an issue really as I have a reasonable access area providing I've cut the strips down first

You don't necessarily have to place it right up against the floorboards, as long as it's sealed round the edges of the room and no draughts get in. You don't need an air gap, but a gap might be useful for wiring and plumbing.

Cheers
Richard

 

[AronSearle]

Floor boards
Joints
about 6 inch of air space
Concrete Garage Roof

Ok, if that 6" air space between the joists and the roof is a sealed area, you could then consider fully filling that void, assuming it's protected from any moisture ingress, you could just blow in loose fibre insulation, you might want a vapour control layer above the insulation, you could run that immediately over the floorboards, the obvious advantage to blown insulation is ease of application and filling all the hard to get areas.

If you stick with celotex, you want it directly under the floorboards, and the air gap underneath the insulation, and that air gap can then be leaky.

geralds method of fitting the panels with expanding foam is highly recommended.

As said if you can seal the edges to prevent air leakage, then an air gap would be OK, but there would still likely be some heat loss around the edges, so it's much better to not have an air gap between the celotex and the floorboards.

 

[geraldthehamster]

As said if you can seal the edges to prevent air leakage, then an air gap would be OK, but there would still likely be some heat loss around the edges, so it's much better to not have an air gap between the celotex and the floorboards.

Fair enough, though if you do need a gap between the boards and the top of the insulation, to run services, you can of course insulate round the edges as well, with an upstand.

Cheers
Richard