Best way to insulate the upstairs of my 60s house

The_Librarian

I live in a 1960s chalet style, tile hung semi detached house very similar to this. The first floor of my home gets very cold in winter, and it appears that behind the wall tiles, there is little more than a membrane, the baton frame for the tiles and then the plasterboard! I have only had a chance to see when changing a socket, but the draft while I did so was worrying...

I am not sure what the best (and preferably cheap) solution would be - to externally insulate (but then it might look 'off' with next door's tiles), try and take the tiles off and put something in between the batons (would this stop any necessary air flow though?), or replace the current plasterboard on the inside with thick insulated stuff (which would then make the rooms smaller, and potentially mean changing the pipework to the radiators, plus the windowsills are very shallow...).

Has anyone got any tips or ideas please?

Edit: My tiles-to-windows ratio is definitely weighted more towards the tiles than the above pic, as I only have one window in the middle of the front wall as there is only one bedroom the full width of the house (but the back of the house looks like the linked photo). The loft is well insulated, but the walls against the tiles are always absolutely Baltic! 

Doozergirl

The cheapest solution will be just insulated plasterboard on its own. 

The proper solution is to rip the existing plaster boards down, put solid insulation between the rafters, ensuring a ventilation gap between the insulation and roof membrane.  In many case you'd add wood to the rafters to enable you to increase the depth of insulation.  

Then you add insulated plasterboard to prevent any thermal breaks from the rafters or gaps between the rafters and solid insulation.  

The ideal depth is 150mm of solid
insulation, including whatever is attached to your insulating plasterboard.  

Energy bills are only going in one direction.  The more you can do, the better.  

FreeBear

If there is a crawl space in the bit of roof below the windows, you could drag some fibreglass/rockwool insulation in. Stuff it between the vertical battens and then use chicken wire to hold it in place - A staple gun will secure the chicken wire.

Grabs39

Very similar to my house.  I wish I had an answer.

I tried to get some insulation for the void under the windows on the scheme last year but was told we weren't eligible, and the cost would have been ridiculous to pay for it in full.

On our sections of sloped roof/wall which are a bit bigger than in that house there is only a void of about an inch-or-so between the plasterboard and the roof membrane (we had a bit of the plasterboard off in the bathroom whilst tiling last year) so I don't think it would be possible to insulate that bit in ours.

I did wonder (too late, after we had the felt replaced) if insulation could be added to the flat roof above the windows.

Following with interest.

FreeBear

Grabs39 said: I did wonder (too late, after we had the felt replaced) if insulation could be added to the flat roof above the windows.

Building Control would have (probably) insisted on insulation if they had been notified.

Basic rule of thumb - If you are removing/replacing more than 25% of a pitched roof, flat roof. plaster/render on an external wall, or ground floor, BC should be notified and extra insulation added where practical.

Grabs39

FreeBear said:

Grabs39 said: I did wonder (too late, after we had the felt replaced) if insulation could be added to the flat roof above the windows.

Building Control would have (probably) insisted on insulation if they had been notified.

Basic rule of thumb - If you are removing/replacing more than 25% of a pitched roof, flat roof. plaster/render on an external wall, or ground floor, BC should be notified and extra insulation added where practical.

Does it count as replacing the roof?  It was just refelted, as is required every few years.

Is it 25% of the roof, or 25% of the small section above the windows?

You live and learn.  I expect we can re-visit in 15 years or so.

FreeBear

Grabs39 said:

FreeBear said:

Grabs39 said: I did wonder (too late, after we had the felt replaced) if insulation could be added to the flat roof above the windows.

Building Control would have (probably) insisted on insulation if they had been notified.

Basic rule of thumb - If you are removing/replacing more than 25% of a pitched roof, flat roof. plaster/render on an external wall, or ground floor, BC should be notified and extra insulation added where practical.

Does it count as replacing the roof?  It was just refelted, as is required every few years.

Is it 25% of the roof, or 25% of the small section above the windows?

Just replacing the felt, you could probably get away with calling it a repair. Replacing the boards as well, that would be classed as a "reroof". If this flat roof is just a small section above a bay or dormer window, then it is a trivial amount, and I wouldn't bother with BC. If you have a flat roof extension elsewhere on the property, you'd fall well under the 25% rule (it is the total flat roof area that they take into account).

Bendy_House

Hi The Lib.

Can you DIY any of this, or will you require builders?

Anyhoo, the same basics apply, in my view.

Yes, the more insulation you can stick in there, the better. Obviously. But there's also a 'cost' versus 'benefit' issue to consider.

To insulate your upstairs 'properly' - ie to current standards - will almost certainly cost you many £ks. And be very disruptive - perhaps requiring extra battens and other mods to your existing walls. You should end up with a very well insulted 'upstairs', but the many £ks you have spent on this will take almost certainly literally decades to recoup. 

So, what you are really realistically after is a noticeable improvement - a genuinely noticeable improvement - but for, ooh, less than £1k? That's still a tough call!

Doozer has outlined how to do this. If you look at that upstairs room from the inside, you will likely notice that the actual amount of 'external' wall is not that much? So, at its simplest, you 'just' need to line these 'external' walls with insulated plasterboard on the inside. At its simplest, you buy a few sheets of TLB (thermal laminate board) - which starts at only around 35mm overall thickness - and you screw it over the internal walls (using ~65mm p'board screws), and then get a plasterer to skim it all. That will make a very noticeable difference. Your walls will no longer be 'baltic', but (reaches over to touch my own walls) quite pleasant to be in contact with. Any 'sloping' ceilings will require ditto.

If you can get access to above the top, flat, ceilings, then just pile normal loft insulation up there, but don't block any ventilation gaps coming up the slopes.

Finally, check your floors. If these are T&G floorboards, then you should seal between each board using cheap frame sealant, and also - more importantly - seal between the bottoms of the skirtings and the floor. Ie STOP THE DRAUGHTS! You may - it's up to you - also wish to add a layer of 8mm low-density fibreboard (the stuff they typically use for laminate flooring underlay) on top, and then replace the flooring of your choice. Basically - stop any bludy draughts coming through.

If you do the above - even with the thinnest TLB - then you will transform the comfort of that room. I say this, as I am sitting in a converted attached garage, which has a single-skin block wall, but which has been converted using the thinnest of TLBs. This room is being heated - to a comfy level - by the heat from my 32" plasma screen...

That's the basics.

If you want to go a step further, then first remove the existing plasterboard layer (quite easy, if messy), and see what you have. I suspect it's bare vertical studs, with nothing but the cold North wind behind it. In which case you can improve things a good step further by snugly cutting sheets of Celotex or similar to fit tightly between these studs, filling any gaps with spray foam adhesive, and then over-boarding with TLB. What thickness of Celo to use is up to you, but say 2" between the studs (stuck level with the front edges of the studs) and then overboarded with at least 35mm, but ideally more, TLB, will 'up' the levels that good bit more.

I've become a believer in the law of diminishing returns... Ie, if this were a new build, then - obviously - stick in the max levels of insulation at this stage (you have to, anyway...), and enjoy the benefits. All you are paying for is the extra thickness of insulation used - so not a huge amount. But, when doing such jobs retrospectively, you do need to weigh up the added costs of the disruption, loss of internal space, extra cost, etc., and compare this with the 'extra' benefits.

Eg, the room I'm sitting in does not 'conform' (even tho' it got 'passed' by BCO...), but for me to make it 'conform' would mean losing another - I dunno, at least 4"? - of internal width (and it's only 8' wide), and I know I wouldn't feel any warmer, and wouldn't notice the tuppence reduction in my monthly bill.

What I've done has transformed this room from a cold dank garage into a super-cosy room with a multitude of uses, and a radiator that's barely turned on, and laying out another ~£k on extra-thick insulation would not have made this any better, only smaller.

To sum up, what I'm saying is - you can transform your room for not a lot. Or you can transform-plus-a-tiny-bit-more for a £hedload, that'll take you many years to recoup :-)