Hire a professional. Not sure about the UK, but in the US ones energy supplier will do a free evaluation of the effectiveness of your insulation, and energy usage. I’d be surprised if it’s not the same in UK
I’ve not heard of that heat-recovery system - probably not a viable option currently as we had a moderate amount of work done a few years ago and have neither the desire or cash for more renovation assuming it would need interconnecting in floor/ceiling spaces, running pipes etc. Perhaps it’s different. I shall Google it later.
We had new glazing put in too without those trickle vents which I thought looked awful.
We had two clearview stoves installed and I was a little annoyed that the installer did not initially suggest or offer the under-grate air intake system which would have been ideal in my view despite added costs. Instead as one was over 5kW outputwe had a large bore vent drilled in the oen plan kitchen lounge area which I’m sure is a source of draught and considerably larger diameter than needed when I did the calculation from the relevant regs, but maybe such things only come in standard sizes. Reasonably confident I could partially block it to a better size.
Yes, probably the best option, though it is something I’d like to have a go doing myself - my back is pretty sore this week so it may need to wait anyway!
Core drills only come in certain sizes - but a large variety (e.g. 100mm, 115mm, 125mm, 150mm - and so there is no excuse for using something significantly oversize, other than lack of awareness of correct requirement, laziness, or poor equipment and/or willingness to obtain or hire the correct size.
Sadly, lack of knowledge or incorrect understanding, lack of innovation, identification of alternatives, etc are common with “professional” installers (with apologies to anyone on the forum who is an installer better than the disinterested majority). That os the other benefit of DIY after cost - provided you do adequate research and understand what you are doing you can do a far better job than commonly done by tradespeople, better planning and better execution and attention to detail, and if as occasionally happens you have to botch something to make it work at least you know exactly what it was done and how good it is.
1 Like
If you have a bungalow with loft then dead easy and very little disruption in rooms, simply a hole bored in ceilings. A standard house with loft and upper rooms aligned with lower is not difficult, but would need a boxed-in duct somewhere like down a corner of each upstairs room.
1 Like
Being a loft insulation maniac, my thoughts are:
1- don’t chuck out what’s there - just re-bed it assuming it’s OK and top up.
2- get some roll/batt-style insulation which has ‘guts’* to it i.e. stuff which is quite stiff, which you can poke in to hard to reach places with a broom - a nice lightweight soft broom is my tool of choice under a shallow pitch (but don’t touch the rafters with the insulation). Measure the joist gaps and get insulation to fit if possible - try and avoid the multi-cut stuff which addresses differing widths.
*c.1995 when I did a previous house, there was a wonderful to use roll (I think Rockwool) which unfurled like a dense thick rug and was very easy to cut. I’ve not seen the same since. I’ve found the DIY sheds only stock the cheaper insulation, which can be a false economy in terms of usability…and it never relaxes out to the stated thickness!
Theory says that if topping up on to a flat surface, such wider rolls could be better but I find they split and when in a loft, cantankerous insulation ain’t what you want.
3- if laying deep i.e. above joist levels (noting 300mm is cited nowadays), get some supports to carry some of the weight of the upper layers and/or do some boarding - the latter can also protect against roof leaks.
Re suspended floors, you can cut in solid insulation between joists, at the same time maintaining ventilation. In some old houses I’ve found that existing vents were inadequate and, in olden times, a lot of fire clinker was emptied under floorboards, which has raised the ground level and generates severe moisture retention.
1 Like
Great responses and tips, thanks all.
If you have a water tank in the loft then you are supposed to leave out insulation beneath it to stop it freezing, but unfortunately this means you loose house heat. Would be great to know what others do about this
In a previous house, mine came with its own insulation blanket and, of course, a lid.
I agree re leaving it clear of insulation underneath. It just meant getting creative in wrapping all around it e.g. using batt-style insulation, which doesn’t lose shape.
Nowadays, it seems the trend is to move to direct mains feeds and sealed CH systems.
How about putting some of this. (or similar) between the rafters. Should keep the loft warmer in the winter and cooler in the summer.
1 Like
That may well be worth a look - equivalent to 55mm polystyrene. Our builder a few years back was banging on about how much insulation would be needed for a loft conversion these days to meet building regs, and while he was initially keen on doing one later backtracked as he hadn’t done one for some time.
No water tanks now since combi boilers - I actually miss the old tanks and hot water cylinder as I find combis so slow for filling a bath - suspect there are hybrid options but seems most fitters just want the quick and easy combi route.
Edit: Actually I don’t miss the tanks in the loft which were well insulated, but when I took a look inside I couldn’t believe the cruddy sediment that was present.
would rather not think about the sediment. I do still like the cylinder idea, as it also gets heated by my solar panels, so free hot water all summer. Combi’s are getting much better, but I also dont like the idea of pressurised systems - for me it just sounds like a more likely potential leak, and a lot more dramatic leak 
1 Like
The pressure guage acts as a leak detector. It doesn’t need much water to leak to drop the pressure enough for the boiler to shut down or fail to fire.
If a gravity fed system leaks, the feed tank keeps filling and the system keeps leaking.
Nice to know, thanks
Please be mindful of the need for ventilation when using any non-breathable stuff.
It may not seem like a roof needs it on the underside but IME many do, as water can ingress during heavy rain/storms and it needs an escape.
I despair when I see the adverts for blowing foam on to the underside of roof tiles and timber - it can just hide issues which come back to bite on the posterior a few years later.
2 Likes
I put a fairly large thermal store in the loft, as it was too big for the bathroom. It came with foam insulation but I was, in any case, going to insulate between the rafters to make the roof space more usable, otherwise putting the water cylinder up there might have caused a lot of heat loss.
The extra storage space in an insulated loft is great, especially for all those empty Naim boxes etc.
1 Like
I used exactly that stuff, but fixed under the rafters rather than in between so that it forms a continuous layer. Also much quicker and easier to fix. (I suspect it’s also the reason we have virtually no mobile phone signal in the house too!)
3 Likes
I got a waste contractor to remove the old insulation which was contaminated with rat droppings (terraced house). The guy putting the new stuff in wouldn’t touch the old stuff.
For water tanks, you put the insulation over the top of the tank, not underneath it.
2 Likes
Interesting observation re the moby signal as I have some friends who’ve had large loft extensions/bought new houses with extensive gables which, doubtless, are fitted with foil wrapped foam board - and they’re always complaining re low/absence of moby signal.
…one of those times when the obvious may be overlooked.
1 Like