Insulating options for a Victorian semi

[S R]

My Victorian semi (c 1873) is not suitable for cavity wall insulation - something to with rubble filling and/or not enough of a cavity. I'm not sure exactly.

However, with huge bills, I have to find a solution.

I am thinking perhaps internal insulation - wall coverings.

I have modern double glazing, yet there is still a discernible draft around the windows, which is probably caused by the wrap-around old wooden window frames. Thinking maybe drilling holes and injecting insulating expanding foam to seal up and gaps and then fill the holes.

The ground floor floor boards leak heat and let in drafts from the cellar. Thinking I should fit insulation under the board between the joists from the cellar ceiling and cover off with plaster board. But I've been warned that the wood needs ventilation to ward off rot.

Does faulty pointing around the external walls affect heat loss by increasing drafts? There are patches that could do with being repaired.

I have thought of temporary measures like stacking bails of hay around the the outside walls during the winter months, but I reckon the neighbours, council and the wife wont like this.

What else? There don't seem to be many retrofitting ideas about.

[harryagain]

You can insulate the whole house internally or externally.

You have to fix all draughts, whatever it takes. If you have fuel bue-rning applicances, you have to pay heed to the ventilation requirements.

[Nightjar]

I suggest you start by getting the application data sheets from Celotex. They cover a whole range of different ways to insulate, including internal and external cladding of solid walls:

If they are the original frames, check that they are not rotten. If they are, they really need to be replaced. If they are sound all it might need is some frame sealant around the outside. The double glazing firm should have ensured they were draught proof when they installed the windows though.

Again, see the Celtox data sheets.

Not normally, but you should re-point anyway as faulty pointing can lead to penetrating damp.

Colin Bignell

[jgh]

Fit some decent carpets.

JGH

[Dave Liquorice]

Or damp walls that will soak up heat to evaporate the water. Draughts might be a problem depending on how solid or not the rubble in fill is. Our "solid" walls do allow air to "circulate" through them, but some might have been standing for 250+ years and the lime mortar is little more than sand...

Cladding the inside of all external walls will be very disruptive but give the best returns. If you can afford to lose 3 to 4" off the rooms then 50 mm of rigid foam insulation bonded to plasterboard will almost bring the place up to recent insulation levels. Even 25 mm of insulation will make a noticeable difference.

Insulating and draught proofing the floors over the cellar might be a better place to start. Various threads in here about that in the past.

Double glazed windows/frames shouldn't be draughty. Draughts are bad but you don't want to hermetically seal the place up, it's an old building it and you! need to be able to breath.

[meow2222]

Internal insulation loses the heat storage effect of the walls, which is of some value in regulating temperature. External is better in this respect, but brings its own issues.

Don't use polystyrene indoors, its a disaster in a fire. Use PIR.

NT

[The Natural Philosopher]

Doesn't work. BTDTGTTS

Optimal solution is to go into cellar and fit celotex underneath the boarding. and fully seal.

next most effective is to lift carpet, tack down hardbaord over floor boards and seal with flexible mastic to skirting, then laygood carpet + underlay.

[dom]

As others have said - rigid foam insulation panels on the interior-side of the exterior walls - Celotex/Kingspan. Check the company websites for the manufacturer guidance on best practice.

I did my chapel conversion, lining all the exterior-facing walls - and it totally transformed the place in terms of warmth and economy.

I already had well-fitted timber-framed double glazing, most air-leaks reasonably sealed, and 250mm loft insulation - but it was the heat-loss through solid masonry walls that was the dominant factor.

However I've never insulated under the original ground floor square-edged board, suspended timber floor (access is too difficult) - and that doesn't seem to be a significant heat-loss.

Either line with plasterboard-faced celotex (minimum loss of space), or fit celotex, studwork and plasterboard (provides cable and pipe routing void).

I did the latter as I need to fully rewire and plumb.

[The Other Mike]

It could be beneficial in some circumstances, burn the place down, get it rebuilt to the latest standards.

[RobertL]

Fixing the drafts should be the first priority. Only when that is done start thinking about other insulation.

If you have any open fires or heaters that use air drawn from the room you will need to be careful not to cut off the incoming air too much.

When insulating I'd first check the loft insulation and also add insulation under the ground floor. Only when they are done woudl I start looking at insulating walls.

Robert

[Martin Pentreath]

I would endorse the idea of insulating under the floor, especially is you h ave the highly "efficient" underfloor ventilation that I have. I did the fl oor of a victorian terrace last year, and it was well worth the effort. The combination of gappy floorboards, open chimneys and sash windows created a n ambiance that could best be described as "bracing". After a fairly unplea sant few days under the floor the room went from being barely habitable for three months of the year, even with the heating on, to being positively co sy.

I got some excellent advice from this group:

[RJH]

Yes, good thread that. A couple of things I picked up:

Plastic sheeting to the ground beneath the floor might be a plan;

Lots of discussion about 'the tiniest gap in underfloor insulation will ruin everything' - makes no sense to me. Gaps would certainly lessen the effect, in much the same way as undoing a button on a shirt. But negate, no. Sealing drafts 'on top', with caulking round skirting, board or sheeting over joists, and decent carpet/underlay seems far more important.

In my case it'd be a *lot* easier to use sheet materials under and across at right angles to the joists, fixed somehow and sealed with tape at the joins. Can't quite figure out whether there'd be a damp problem with that method though.

[The Natural Philosopher]

personal experience and even crude calculations shows that this is almost correct.

If it leaves a draught.

[js.b1]

The comments about internally insulating exterior walls losing thermal mass is not correct - you retain the thermal mass of the INTERNAL walls (which is large).

To meet current BR you would need to put something like 65mm celotex on the inside of your walls, this can cause a problem in north facing heavy wind driven locations with joints embedded in the wall - the dew point can move so far into the wall the joists rot off. Thus far it is only the highest gr ade exposure sites which have thrown this up (West Coast of Ireland with ho rizontal coastal wind & rain). However there is a time issue.

If you can insulate 40mm Extruded Polystyrene on all external walls, the di fference will be simply night & day. I would aim for 40mm Celotex or 50mm E xtruded Polystyrene, start with the main living area, then the bedroom, the n the hall. Roof, well if the roof leaks 1% moisture in rockwool = 0% ins ulation value pretty much, so tackle any roof leaks and ensure that is both insulated AND adequately ventilated.

[george - dicegeorge]

On 09/09/13 01:27, S R wrote: xxxx

Dont use normal foam which expands 10 times and may damage your windows, pinkgrip is better as it only expands about once.

Get an infrared heat gun from maplins- it points a red light on your wall and tells you the temperature, so on a cold day you can see where the heat is escaping and wheres the most important place to insulate.

good book is the canadian

[george]

[RJH]

Well. Personal experience is worth knowing. But context is all.

On to the more empirical. Which calculations? And what does 'leave a draught' mean? A draught involves passage of air. How does a cul de sac gap lead to passage of air? I readily accept cold spots (and attendant problems). But to the extent of 'almost negate'. Just don't get it.

I accept that you have a point. But I think you're overstating it to a ridiculous extent.

[RJH]

Expanding foam is fine, except in application and removal ;-)

Yep, agreed. Cheap and easy.