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Two parts, first this, has anyone tried and had any luck?
https://www.gov.uk/apply-great-british-insulation-scheme
Second the house has the grand total of 40mm If I am generous. Would I be better stripping it out and replacing with 100mm then a 200mm layer? Or just sticking the 100 on the 40mm then adding the 200?
When I redid mine I left the original in there. The thought of stripping out a load of glass wool is ghastly, and then you've got to get rid of it.
Re the grant I suspect it involves a contractor doing it for you, which in my experience can be sub optimal. My dad had it done and they blocked up all the air vents with insulation. Personally I'd rather do it myself but ymmv
I'm in a very similar position.
I think I'm essentially just going to roll out new insulation on top of the old stuff, leaving a suitable gap around the edges to maintain ventillation to the 'eaves'? Shifting the odd cable ontop of the new stuff etc. rather then burying it. check any ceiling mounted light fittings to the floor below have some sort of 'shield' of 'guard' arround them.
It's not actually that expensive and if you plan it out properly before hand, buy a disposable paper jump suit, gloves, goggles and mask, it's propbably only an hour or two of actual work in the attic.
I'm half tempted to put some risers/stilts up there too, so I can put a couple of boards above the new insulation for storage. And make future visits up into the loft less precarious....But I've not decided on that yet.
Just put it on top.
Mine took ages as it was a 1930s house and all the gaps between the rafters were different widths. A lot of cutting with a bread knife.
Check what spacing the stilts needed as well. I ended using loads and you need 4 screws for each.
When I first did mine I used those sausages of glass wool in a plastic case, they were 2 for 1 in b and q about this time of year. Handling was not too bad, they puff up nicely. When I topped it up recently I used recycled plastic wool which was a dream to use. It cost more but was a joy to work with.
As above I kept vents clear, relocated a few cables and dealt with ceiling lights. The loft legs were easy to fit and the extra insulation has made a big and very noticeable difference. Don't forget the loft hatch, I stuck on some skip dived celotex
I ended up boarding the whole loft and got a light put in. Absolute best money I've spent on the house I reckon
I took out about 400mm of rat pee and poo covered glassfibre from my house, bagging it up and to the tip. Then we did various cleaning up / repairs / improvements / electrics before laying 270mm of new stuff.
Removing the old stuff was a solid day and a half of thoroughly unpleasant activity in long sleeves, a paper suit, mask goggles and gloves during the summer heat, 2 van loads to the tip (thankfully free) - each tip run was about 70 rubble sacks in the van.
Laying the new stuff was about a days work - first layer that goes between the joists obviously a bit more faffing with cutting and fitting between them, second layer was like an hour or so as it was basically just take the roll to one end of the loft and punt it to roll it out.
Current building regs stipulate 270mm so we did that.
If you do decided to remove the oldest stuff, get an asbestos test kit first!
Yeah, thats partly why I'm thinking of leaving the existing 'thin layer' of insulation in place, (it's level with the joists) and putting a new layer on top of it...
The thought of pulling up, and disposing of the crappy old stuff just fills me with dread, with all the dust and glass fibres it will kick into the air.
Maybe not the best or most professinal way to do it, but it's the path of least resistance as the existing stuff is not damp or degraded or anything that I can tell...its just old and has a LOT of dust on the surface.
I also just put new on top of old. Seems fine. +1 for the lovely recycled plastic bottle insulation - it really is so much nicer than glass fibre.
ovely recycled plastic bottle insulation – it really is so much nicer than glass fibre.
I totally get this, but at B&q it works out at about £10 per square meter, where as the nasty glass wool stuff is only about £2.50 per squre meter for the cheapest stuff... they seem to have some mid priced ones inbetween those prices, so it's kinda difficult to know what to get for the best, as in least 'effort Vs cost'.
Leave the old. It saves needing to get a thin first layer and splitting it to slot between the joists. The new layer can go in the other direction and this increases effectiveness.
We got ours done free under grant with a contractor, we are in a bungalow so the roof area is double the size and set just squeaked in within the maximum area allowable, so a fair cost in materials. The contractor was fine and they also fitted plastic spacers in the felt to add ventilation, and didn't block the eaves.
I wish I'd added stilts and catwalks to get to some of the stuff at the end of the loft, such as TV aerial and loft mounted extractors, I was walking over it on the joists and it's crushed it in a few places.
thanks for the comments, I spent this afternoon removing all kinds of crap, like carpet placed on top of insulation in some kind of it'll add some insulation value sort of way.
So I'll just go for the easy route. got some rolls of 100mm from B&Q which I'll fit when I have a moment then make another trip and get the thicker stuff.
On the boarding thing, any reason why I can't do this at a later date when I have more reason to do it? At the moment I don't have much junk I need to dump in the loft?
Yeah I think boarding would be easier now. Once it's all in you'll need to locate joists to attach the legs which would be a right pain as they'll be covered by potentially 2 layers of insulation at right angles to one another.
I'm sure people do it that way but it seemed easier the other way
Also you'll squash the wool when you bring material up and stack it
It's easier to put the legs on before the top layer, and you need quite a lot of legs.
Top tip I saw on YouTube: cut the bottom layer to width while still in the packaging/roll, use a bread knife or fine toothed saw
Current building regs stipulate 270mm so we did that.
The Swedes use 400mm our building regs are a bare minimum and a compromise between what keeps the heat in and how much the house-building companies are prepared to pay. More is definitely better.
Here's the Swedish recommendations.
It’s easier to put the legs on before the top layer, and you need quite a lot of legs.
This seems the most sensible way, so you're not trying to pull up your new insulation to fit/drill the legs in at a later date.
I'm just thinking of putting a bit of a cat-walk/ storage area down, rather than boarding out the whole thing though.
I think I read that you need to leave an air gap between the top of the insulation and any boarding too, so you'll need to take that into account when specifying the height of the legs, ie. any boards you put down shouldn't be in contact with or compressing the insulation.
Good timing of this thread.
Looked at the link.....knocked on the head straight away....Band A to D.....I'm band E.....humphh.
Interesting what you say about a contracter covering air vents.
My house is constructed with the roof joists sitting on the iner cavity wall, meaning that there is no exposed joist ends or soffit panels. The outer brickwork has 3 'sailing' courses of bricks, with the gutter fixed directly to the final course.
So, I would also be worried if the insulation covered the open gap that you can see when in the loft, as that being open is part of the breathability of the cavity.
At the moment there is no insulation at joist/ceiling level, but is ready attached to the tile underfelt. (House built in mid '70's. Looks like they made underfelt with insulation. Neighbours are all the same, so not a later DIY add on).
I was thinking along the lines of https://www.wickes.co.uk/Kingspan-TP10-Roof-Insulation-Board---2400-x-1200-x-100mm/p/180438 or https://www.travisperkins.co.uk/cavity-and-internal-wall-insulation/knauf-dritherm-cavity-slab-37-100mm-455-x-1200mm-6-55m2-per-pack/p/848602 cut into strips to fit between inbetween the joists, sittting on the plasterboard.
There are ceiling lights in the bathroom, so I would want to cut around those.
Less messy than rolls of loose fibre loft insulation?
Alternative to stilts is to lay new joists across the old ones.
I did a job for a client who wanted insulation boards between joists a bit like that. It was a total pain to cut and fit each one without gaps. If they are reasonably soft and pliable then maybe, but the wool type method let's you mold it around awkward areas and won't leave gaps. Cutting insulation can be surprisingly hard work
Less messy than rolls of loose fibre loft insulation
Less messy for sure but...
£55.03
per pack
Length 1200 mm
Thickness100 mm
Width 455 mm
Whats that, over £50 per square meter? ouch!
EDIT...ignore me.. in the small print you get Pack Quantity = 12
That's what really pisses me off.. they should do it like in the EU where the main price is £ per litre or £ per meter etc... it would save a lot of bother.
Doh! And here was me thinking this stuff was expensive:
https://www.diy.com/departments/diall-insulation-roll-l-6m-w-0-37m-t-100mm/3663602481812_BQ.prd
I've got those round soffit vents. Is it important to keep just the space above these clear, or should there be a 'moat' of clear space around the entire loft edge and any subsequent boarding out on the stilts?
@mrmo - Meant to say I applied to the GOV insulation scheme, and all accepted, but Octopus Energy haven't got in touch in the timeframe suggested. I'll give them a call this week to see how things lie.
Current building regs stipulate 270mm so we did that.
I understand that building regs were changed last summer and that the new fibreglass depth equivalent is 450mm.
Haven't checked the approved documents myself yet.
These are the vents that allow ventilation past the insulation.
Alternative to stilts is to lay new joists across the old ones.
That gets surprisingly expensive very quickly and takes an age to complete. (I may have firred the joists in my loft to 150mm from 100mm the first time around).
Trust me on this the loft legs are much quicker and cheaper. Despite being grown on trees sawn timber costs get chunky quickly even going via a sawmill. Then there's all the drilling for some very long screws to avoid splitting joists or firring strips.
OP Celtic Sustainables for legs in bulk were cheapest earlier this year.
getting long timbers into a roof is good fun for the most people as well.
I put new on top of old, but then it was a new build at the time. No issues.
I also made a suspended floor by bolting timbers onto the down members of the trusses.
When I topped up our loft insulation last year I added 170mm to the existing 200m that was already down. At the same time I added some Loft Leg XL loft legs which I are 300mm, providing a decent sized air gap with the 370mm insulation we now have.
I only boarded a small section as it's a very small loft space and we just wanted somewhere to store camping gear and Christmas decorations. But I'd agree it's much easier to install the legs when the joists are exposed.
I've also applied for the Great British Insulation Scheme and am waiting to hear back from Octopus as we are in a dormer bungalow and are interested in room in roof insulation.
I’ve also applied for the Great British Insulation Scheme and am waiting to hear back from Octopus as we are in a dormer bungalow and are interested in room in roof insulation.
Thanks for mentioning this. I think we might be eligible too so keen on this.
Alternative to stilts is to lay new joists across the old ones.
That gets surprisingly expensive very quickly and takes an age to complete. (I may have firred the joists in my loft to 150mm from 100mm the first time around).
I've done this recently - £3.80/m. Cheaper than the loft legs I could find.
Then there’s all the drilling for some very long screws to avoid splitting joists or firring strips.
I didn't fix them down, once the boarding is on top and screwed down it is a rigid box, rock solid.
getting long timbers into a roof is good fun for the most people as well.
I cut them before I took them up to the loft.
slight side jack
my loft is already minimally insulated but mostly boarded.. so the idea of adding anything else to ceiling level is a no go to me...the house doesnt struggle too badly anyway, mid terrace... i wondered if it was worth putting anything between the roof joists? and if so the most cost effective and simplest way? my guut feeling is getting a contracter to spray foame these areas is possibly the best shout
I cold also do with doing hte front and rear, basically between the ground floor windows and upper windows to the roof line i have nothing but fascia boards, and i had to put some back up last year, all the was behind these areas was basically rubble..i guess hte houe is mostly constructed from the left nad right walls rather than front to back. i need to take the front fasica iff and refit so was wondering about putting some sort of thin insutlation sheeting across the area, i guess blobs of grip fill or sealant wold be enough to hold it in place until the fascia boarding went back up?
any thoughts?
my guut feeling is getting a contracter to spray foame these areas is possibly the best shout
As with any type of insulation, you need to make sure that the roof is dry and in good condition before adding any insulation. Also, right now many mortgage companies aren’t willing to offer loans for properties with foam insulation in the roof, which can make it very difficult to sell a property with this type of insulation.
Possibly worth investigating? (above from Energy Saving Trust)
The thought of pulling up, and disposing of the crappy old stuff just fills me with dread, with all the dust and glass fibres it will kick into the air.
When we moved into our current house the subsidised scheme at the time would only pay if your loft had no exising insulation, so I removed the probably 50mm of dirty crap that was up there. It was the most horrible, itchy and dirty job I think I've ever done.
Then I tore the bottom out of one of the bags on the stepladder and dumped the contents through the hall, stairs landing. Oh how my missis laughed. 🙄
my guut feeling is getting a contracter to spray foame these areas is possibly the best shout
Don't know if someone will have commented while I've been reading/typing, but this is probably the very worst thing you could do for your roof. I've got no suggestion on how to do it properly, but this is NOT the way to go. Causes massive condensation problems and no roofer will touch any future repairs.
see, didnt know this was a bad idea
ive seen plenty of videos of it being done in that exact location 😀
Its a messy job with all of the dust, so i'd be adding as much insulation as you can in one go.
I added an additional 200m on top of the 100mm already there.
Its made a significant difference and means I dont have to bother going up into the attic again
my guut feeling is getting a contracter to spray foam these areas is possibly the best shout
As others have said, this is the worst idea ever. Next time its cold and rains have a look up in the attic and look at the tiles and there is likely to be condensation on them. The foam just makes that condensation soak into the joins and rot them.
Just done ours with 170mm Knauf insulation from Wickes, didn’t need gloves etc not at all unpleasant to work with and £24 per pack, much better price than B+Q. Delivered free as I spent over £100.
If you are installing it yourself, I recommend an insulation knife.
I use a Morakniv Insulation Knife 7350*
This allows you to cleanly cut the rolls into widths to fit between the rafters. Then just roll out for a snug fit.
*Other insulation knifes are available
I've applied through https://octopus.energy/great-british-insulation-scheme/ as mentioned further up the thread and had an initial call after about 6 weeks just confirming a few details, has anyone gone through the full process and what did they end up paying for loft insulation? I guess you're at the mercy of a local contractor?
Still waiting for contact from Octopus (or their partner) after qualifying for GBIS. Was told 12 weeks for a response about 6 weeks ago.