How to insulate 1960s flat?

[Sad S]

Two questions for you. I am considering making an offer on a flat in a 1960s system built block.

This particular flat has been well looked after by its owner occupiers.

However another flat in the same block, which has been let, shows damp and mould on external walls in living room and bedrooms.
Big windows, all now with double glazed UPVC windows. But walls under the windows are cold.
What could be done to improve heat insulation in such a building? The EPC reads 52 at present, with potential to get it up to 77 - but how?

Also, noise transmission between flats could be a problem. I doubt if anything could be done about vertical transmission, becasue there is no spare room height; but can something be added to what seem like plasterboard walls between flats on the same level, to keep noise down?

Grateful for any ideas or observations.

[mk1fan]

Ask a Building Surveyor to inspect the flat and propose solutions for your queries.

[Sad S]

I am considering making an offer on a flat in a 1960s system built block.



Not yet at the stage of sending a surveyor round, no offer has been made or accepted. Clearly mk1fan's suggestion should yield the most authoritative advice. But I don't want to waste £600 in surveyor's fees, and a month of everybody's time, making an offer and then withdrawing it if the exercise is clearly pointless and nothing effective can be done.

So - has anyone knowledge or experience of this situation?

[mind the gap]

What could be done to improve heat insulation in such a building? The EPC reads 52 at present, with potential to get it up to 77 - but how?



Read on, not just the first page of the EPC! The whole EPC report will tell you the practical measures which could be implemented in order to achieve 77%. They only suggest measures which are cost effective in 5 years, too, nothing silly or prohibitively expensive. Usual areas are insulation of lofts (not applicable here presumably, unless a top storey flat?), cavit wall insulation, new boiler if old one v.ineffcient, thermostatic valves on radiators, and so on.

[bandontherun]

Cavity wall insulation is a non runner in a block of flats unless you can get every flat owner on board; which will be difficult to say the least!

In such a case your best bet is to pull the skirtings off and line (from within the flat) the outside walls with a phenolic foam backed plasterboard such as Thermaline Super (30mms thick). You will achieve superior insulation without the risks of slumped soggy fluff for which the Cavity Wall Injecting fraternity will decline responsibility and blame on poor management of your block's rainwater goods; or bridging of the DPC. The cavity in the building was designed so that an outer wall exposed to driving rain and soaking wet will be isolated by air from your inner leaf and filling the cavity with fluff is not without risk, as the insulant can get wet and slump down. Needless to say this is not something they spell out when selling the systems but speak to a builder who has been on the tools for long enough and he is likely to be less sanguine than most of the wisdom of pumping fluff into cavities that were not designed for that very purpose. Once the insulant slumps it generally has to be sucked out from the foot of the cavity

I would recommend drylining internally with thermaline super or Kingspan kooltherm as a much better route.

If ground floor flat (on a concrete slab) the floor should be insulated; we've had good success with thin multifoil systems.

If the double glazing in situ is old, it may be worth upgrading! This might sound like a waste of money but the difference between 15 year old double glazing and the best stuff fitted today is like night and day. This is especially so if noise attenuation is a factor. It has been discovered that if the two sheets of glass are of a thickness which differs by more than a third, the amount of sound which carries through (as compared to two identical thickness of glass) is reduced by two thirds as two sheets of glass of the same thickness offer a far less resistance to a particular noise frequency than two sheets of differing thicknesses.

If you are upgrading double glazing specify that you want the outer face of the inner leaf soft coated with the space between the glass >12mms and the cavity filled with argon. At risk of sounding like an insulation anorak we have reduced energy consumption in 1960s flats with measures such as those above by considerably better than 50%.

Dry lining with ultra insulating plasterboards can also cover a multititude of decorative nightmares, when refurbishing

[Sad S]

Thanks for the suggestions.

Bandontherun - would any builder be able to install these insulating plasterboards, or should I seek out a specialist?

[bandontherun]

Its very very easy. just a dab of plaster every few inches... and they stick to the old wall. you don't need any mechanical fixings but the odd screw is I think a good idea

any builder will be able to do it. really straightforward. you'll be amazed!

[mind the gap]

Its very very easy. just a dab of plaster every few inches... and they stick to the old wall. you don't need any mechanical fixings but the odd screw is I think a good idea

any builder will be able to do it. really straightforward. you'll be amazed!

They are indeed very effective thermally, but they do of course reduce the dimensions of the room - only ideal when the rooms are large enough to lose a couple of inches all round without noticing it.

What's the boiler and heating system like?

[mk1fan]

Any 'improvements' need to be suitable for the actual property. Although generally speaking the above suggestions may seem sensible there is the possibility that they may not work for this particular property.

Replaceing windows in a block of flats should be done 'on mass' to maintain a consistent appearance of the whole property. It also requires Planning Consent - although both these are widely ignored.

Dry lining with insulated plasterboard needs carefull consideration. Electrics need to be brought forward and properly sealed - you don't want to create a damp zone behind the new board.

If you're only 'considering' making an offer then make the decision based upon it's current form and ignore the 'potential'. If you decide to proceed then instruct your Surveyor to also assess and comment on 'environmental' improvements.

[Sad S]

They are indeed very effective thermally, but they do of course reduce the dimensions of the room - only ideal when the rooms are large enough to lose a couple of inches all round without noticing it.

What's the boiler and heating system like?

Undoubtedly the loss of a couple of inches all round would be noticed. But since there are three more floors above, and the ceiling really has no leeway above window frames, it wouldn't be possible to extra insulate the ceiling: it might make little difference in any case.

There's no boiler. There's no gas in the block. All electric - night storage heaters all round, additional wall mounted convector in living room, immersion heater for hot water.

My main concern is the potential for damp and mould. If tenants to fail adequately to ventilate the property, which has very cold surfaces on each external wall because of the poor insulation, then damp and mould will surely follow.

[Sad S]

Any 'improvements' need to be suitable for the actual property. Although generally speaking the above suggestions may seem sensible there is the possibility that they may not work for this particular property.

Replaceing windows in a block of flats should be done 'on mass' to maintain a consistent appearance of the whole property. It also requires Planning Consent - although both these are widely ignored.

Dry lining with insulated plasterboard needs carefull consideration. Electrics need to be brought forward and properly sealed - you don't want to create a damp zone behind the new board.

If you're only 'considering' making an offer then make the decision based upon it's current form and ignore the 'potential'. If you decide to proceed then instruct your Surveyor to also assess and comment on 'environmental' improvements.

Thanks for that. Will bear it in mind.

[Sad S]

Just out of interest, I checked the Energy Bill, to find that it's now the Energy Act 2011.
It has the following provision:


"Private rented sector

"* The Act includes provisions to ensure that from April 2016, private residential landlords will be unable to refuse a tenant's reasonable request for consent to energy efficiency improvements where a finance package, such as the Green Deal and/or the Energy Company Obligation (ECO), is available.
"* Provisions in the Act also provide for powers to ensure that from April 2018, it will be unlawful to rent out a residential or business premise that does not reach a minimum energy efficiency standard (the intention is for this to be set at EPC rating 'E')."

Band E is 39-54. But who knows what will happen?

[mk1fan]

Assumingthe building isn't listed in some way. There's no reason why you can drop the existing ceilings, install mineral wool insulation between the (assumed) floor joists and reinstating a new ceiling. Indeed it could be a significant improvement for both thermal, sound and fire insulation. I would suggest (for performance) using rockwool on chicken wire and a 12.5mm thick fireboard. Should still leave enough space to run your electric cables below and upstairs cables above. If you're going to fit downlighters fit a fire rated item such as those from Sylvania and fit SMD LED bulbs as they don't generate a lot of heat. They also use little electric.

You may want to consider fitting some electric flat panel heaters too to back up the night storage. A 270W version would provide a good boost. Don't underestimate the effect a simple 'S' type electric towel rail. I have a 60W item fitted in a shower room that the tenants leave on and the room is (even now) warm enough.

Secondary glazing would improve matters and not effect the external of the property.

I'd get onto the Freeholder about adding cavity wall insulation as part of the next round of maintenance works.

Instead of installing 'normal' through the wall extractor fans fit heat recovery versions. Xpelair do a range that are very reasonably priced for what they do. These would help remove condensation related damp although you'll need to check the pollen filters yearly.

Again though, these need to be considered in relation to the actual property.

[bandontherun]

the whole point about thermalite super is that its more insulative than cavity wall filling at a combined thickness of insulant and plasterboard of 27mms; so you dont lose a couple of inches all round; merely just over an inch!

[bandontherun]

band e is pretty low. It's not hard to get most places up to C or D, but you will have to spend some money. Bunging a thermal panel on the roof to produce sustainable electricity or warm water will jump you up by a grade, but obviously that is not possible in every instance.

Listed and conservation area properties are much more challenging but progress can be made. Sempertap is not as insulative as phenolic boards but it will go round lumps and bumps in old walls and the difference will still be tangible

[mk1fan]

the whole point about thermalite super is that its more insulative than cavity wall filling at a combined thickness of insulant and plasterboard of 27mms; so you dont lose a couple of inches all round; merely just over an inch!

Imagine doing both! Dry lining internally needs to be carried out by someone who'll make the effort to do it all 'right' rather than just slap it up. There are minor disadvantages that need to be considered. Fixing items such as shelves or cabinets will require more work but nothing complicated.

The 27mm boards are really only 'thermal break' boards for window reveals. Having said that I have just fitted them in a Victorian house with solid walls as they were the 'right thickness'.

[Interlaken]

In the last 2 years I have applied Thinsulex (as used in Warm Roof applications) to existing plaster walls/sloping ceilings with battens then thermal plasterboard and finish over the top with excellent results. I did this in an Edwardian property and on the outside N facing wall in an early 80's Barratt house which is all electric.

Yes there is loss of a few inches all around but the heat retention is remarkable. Well worth the cost and effort as both properties were getting complaints in winter.