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Opinions from the hive mind requested.
We've recently moved into a house we intend to stay in for much of the rest of our lives. It's a three-storey with the top floor partly in-roof, so the top rooms have some sloped ceiling but a smallish attic space above. The insulation is awful: I've burned about twice as much wood as we did in our last place, and felt much colder, despite it being a really quite mild winter.
So, filling the (currently empty) cavity walls and doing some serious topping up of the loft insulation seems a good plan.
Question 1: on googling this I am presented with a multitude of links promising both cavity walls and loft insulation for free. I have no idea if these firms are genuinely presenting an opportunity to get the work done for free, or if they're a bunch of cowboys, or something inbetween. Has anyone actually had this done for free?
I've just had a nice chap from a UK-wide firm around, who told me that there's no chance of getting any grants as my house is too young (built 1986). He's just quoted £900 for cavity wall insulation - said it was expensive compared to most because he'd need to use fancy bead insulation to minimise drilling (some of the walls will need to be drilled from the inside as outside elevations are inaccessible). Also quoted £700 to raise my existing loft joists by an additional 50mm, bringing them to 150mm, and then boarding with 18mm insulating board; he thinks this will give equivalent total insulation to 250mm of quilt.
Question 2: are these prices remotely what I should expect? I can go get more quotes, but it's all a bloody faff - so I'd like to know if these seem to be in the right ball park.
Cheers
Jamie
We've recently moved into a house we intend to stay in for much of the rest of our lives. It's a three-storey with the top floor partly in-roof, so the top rooms have some sloped ceiling but a smallish attic space above. The insulation is awful: I've burned about twice as much wood as we did in our last place, and felt much colder, despite it being a really quite mild winter.
So, filling the (currently empty) cavity walls and doing some serious topping up of the loft insulation seems a good plan.
Question 1: on googling this I am presented with a multitude of links promising both cavity walls and loft insulation for free. I have no idea if these firms are genuinely presenting an opportunity to get the work done for free, or if they're a bunch of cowboys, or something inbetween. Has anyone actually had this done for free?
I've just had a nice chap from a UK-wide firm around, who told me that there's no chance of getting any grants as my house is too young (built 1986). He's just quoted £900 for cavity wall insulation - said it was expensive compared to most because he'd need to use fancy bead insulation to minimise drilling (some of the walls will need to be drilled from the inside as outside elevations are inaccessible). Also quoted £700 to raise my existing loft joists by an additional 50mm, bringing them to 150mm, and then boarding with 18mm insulating board; he thinks this will give equivalent total insulation to 250mm of quilt.
Question 2: are these prices remotely what I should expect? I can go get more quotes, but it's all a bloody faff - so I'd like to know if these seem to be in the right ball park.
Cheers
Jamie
In reply to Jamie Wakeham:
Assuming the loft isn't tiny that seems a reasonable ish quote for timber, insulation, labour and VAT. That said, it's not a difficult job to DIY though you (or the contractor) may need to consider re-routing cables or at least checking the suitability of the fusing/cable for burial in insulation.
No idea about the cavity walls or grants.
jk
Assuming the loft isn't tiny that seems a reasonable ish quote for timber, insulation, labour and VAT. That said, it's not a difficult job to DIY though you (or the contractor) may need to consider re-routing cables or at least checking the suitability of the fusing/cable for burial in insulation.
No idea about the cavity walls or grants.
jk
In reply to Jamie Wakeham:
Hi,
Yes the free stuff is genuine and based on government grants which you may or may not get (google it).
Why do you want to raise the floor level in the loft, most people just pile the insulation high and only board out a smaller section for storing stuff? To be honest the smaller amount of insulation + the loft boards is reasonable insulation anyhow and you can always put more on top of areas you aren't using for storage.
Cavity wall wise I think it's a lot cheaper if you use the normal injection foam, but like you say if you have to do it from the inside then you will end up with some holes to redecorate over.
Hi,
Yes the free stuff is genuine and based on government grants which you may or may not get (google it).
Why do you want to raise the floor level in the loft, most people just pile the insulation high and only board out a smaller section for storing stuff? To be honest the smaller amount of insulation + the loft boards is reasonable insulation anyhow and you can always put more on top of areas you aren't using for storage.
Cavity wall wise I think it's a lot cheaper if you use the normal injection foam, but like you say if you have to do it from the inside then you will end up with some holes to redecorate over.
In reply to Jamie Wakeham:
Have a google about condensation problems with loft insulation. If you overdo it, or do it wrong, you can end up with damp timbers that may rot and be *very* expensive to fix.
Have a google about condensation problems with loft insulation. If you overdo it, or do it wrong, you can end up with damp timbers that may rot and be *very* expensive to fix.
6
In reply to Jamie Wakeham:
I have seen some horrendous condensation problems develop with cavity wall insulation but you can get air management systems to overcome this (about £1000, installed). I don't know what surface area the loft is but that doesn't sound unreasonable (having dome something similar myself for a not dissimilar amount of money).
Have you done the cloakroom-cellar conversion yet?
I have seen some horrendous condensation problems develop with cavity wall insulation but you can get air management systems to overcome this (about £1000, installed). I don't know what surface area the loft is but that doesn't sound unreasonable (having dome something similar myself for a not dissimilar amount of money).
Have you done the cloakroom-cellar conversion yet?
In reply to Jamie Wakeham:
The insulation work we had done was as part of a much wider rebuild, so prices aren't directly comparable but your quotes don't seem wildly out of line with the component of ours related to similar works on the walls and the labour costs for replacing joist equivalent to perhaps a 2 bedroom house (similar amount of labour to raising joists I expect.)
In the fine tradition of giving probably unwanted advice that doesn't answer your questions: If you're going to insulate walls thinking carefully about cooling in summer (what's your daily electrical power consumption? That largely ends up as heat inside the house. How much sunlight comes in to the house?) and make sure you don't engineer a hotbox. Friends of ours in well insulated new builds can't passively cool them to what I consider a comfortable temperature (~18oC) for a significant fraction of the year.
On the flip side, insulation works best if you make sure windows, walls and the like are airtight and don't exchange air with the outside world at an astounding rate. If you do make the house relatively air tight, you then have significantly more problems with condensation and mold - likely to be particularly prominent in bathroom/kitchen areas and on any areas of wall that for whatever reason are not as well insulated. For example the corners of walls will have more solid brick and less cavity, so you may expect the corners of your bedroom and bathroom to condense a lot of moisture. You might consider replacing the plaster on the walls in corners with insulated plasterboard the next time you redecorate.
Yo should think about a mechanical ventilation system with heat recovery so you don't have to open the windows and let all the heat out. We fitted a KAir to our bathroom and it works wonders - http://www.kair.co.uk/product/kair-heat-recovery-room-ventilator/ - for the kitchen I just open windows which isn't so bad for economy as I'm a miser and don't use the heating in there as the waste heat from cooking is plenty.
The insulation work we had done was as part of a much wider rebuild, so prices aren't directly comparable but your quotes don't seem wildly out of line with the component of ours related to similar works on the walls and the labour costs for replacing joist equivalent to perhaps a 2 bedroom house (similar amount of labour to raising joists I expect.)
In the fine tradition of giving probably unwanted advice that doesn't answer your questions: If you're going to insulate walls thinking carefully about cooling in summer (what's your daily electrical power consumption? That largely ends up as heat inside the house. How much sunlight comes in to the house?) and make sure you don't engineer a hotbox. Friends of ours in well insulated new builds can't passively cool them to what I consider a comfortable temperature (~18oC) for a significant fraction of the year.
On the flip side, insulation works best if you make sure windows, walls and the like are airtight and don't exchange air with the outside world at an astounding rate. If you do make the house relatively air tight, you then have significantly more problems with condensation and mold - likely to be particularly prominent in bathroom/kitchen areas and on any areas of wall that for whatever reason are not as well insulated. For example the corners of walls will have more solid brick and less cavity, so you may expect the corners of your bedroom and bathroom to condense a lot of moisture. You might consider replacing the plaster on the walls in corners with insulated plasterboard the next time you redecorate.
Yo should think about a mechanical ventilation system with heat recovery so you don't have to open the windows and let all the heat out. We fitted a KAir to our bathroom and it works wonders - http://www.kair.co.uk/product/kair-heat-recovery-room-ventilator/ - for the kitchen I just open windows which isn't so bad for economy as I'm a miser and don't use the heating in there as the waste heat from cooking is plenty.
1
In reply to Jamie Wakeham:
Not sure about the free / grant thing, but the prices quoted don't seem too bad, but I don't understand the following part:
What sort of board is he talking about?
If the house was built in 1986 I'd have expected there to be some cavity insulation in place at the time of construction. Has anyone checked what's in there? There are very mixed experiences with retro-installed cavity insulation, so I'd tend to go down other paths to improve thermal insulation if I were you. And contrary to what was stated in an earlier post, corners should be no less insulated than the main areas of external wall - the cavity should be continuous.
Not sure about the free / grant thing, but the prices quoted don't seem too bad, but I don't understand the following part:
> ... then boarding with 18mm insulating board; he thinks this will give equivalent total insulation to 250mm of quilt.
What sort of board is he talking about?
If the house was built in 1986 I'd have expected there to be some cavity insulation in place at the time of construction. Has anyone checked what's in there? There are very mixed experiences with retro-installed cavity insulation, so I'd tend to go down other paths to improve thermal insulation if I were you. And contrary to what was stated in an earlier post, corners should be no less insulated than the main areas of external wall - the cavity should be continuous.
In reply to Jamie Wakeham:
One thing to consider is that cavity walls are empty for a reason, they allow any water which penetrates the outer leaf to drain down the inside of the outer leaf and out of the weep hole vents (if you have them). Filling a cavity can cause damp penetration problems IF the wall is susceptible - i.e. if it is exposed to driving rain (West facing and windy), or if the construction has pathways for water to enter (dodgy mortar joints/ porous materials), or if there are already damp issues such a DPC is not present or has been breached, or dodgy rainwater drainage which are currently being abated by the fact that the cavity is empty. If you're happy that none of these apply and can't see any other issues with this, then go for the cavity insulation.
Not sure what what you mean by this, 18mm board sounds like chipboard - is he talking about 18mm chipboard with 150mm of insulation bonded to the back of it? Do you need a solid deck for storage? if not you could just lay the equivalent insulation in between and on top of the joists without increasing their depth. If you have a shower room or otherwise lots of moisture on the top floor you should install a vapour barrier below the new insulation so that moisture doesn't condense inside your roof void (or inside your joists even). There are a few ways to do this:
1) Apply 2 coats of drywall sealer to the ceiling below (although this presumes you are re-decorating)
2) put a vapour barrier below the insulation (i.e. visqueen sheets with taped joints)
3) use insulation that has a vapour barrier fixed to the bottom of it (like foil) or is itself of low vapour permeability (generally any closed cell foam)
no.2 is probably the easiest. Also is the roof void well ventilated?
> So, filling the (currently empty) cavity walls and doing some serious topping up of the loft insulation seems a good plan.
One thing to consider is that cavity walls are empty for a reason, they allow any water which penetrates the outer leaf to drain down the inside of the outer leaf and out of the weep hole vents (if you have them). Filling a cavity can cause damp penetration problems IF the wall is susceptible - i.e. if it is exposed to driving rain (West facing and windy), or if the construction has pathways for water to enter (dodgy mortar joints/ porous materials), or if there are already damp issues such a DPC is not present or has been breached, or dodgy rainwater drainage which are currently being abated by the fact that the cavity is empty. If you're happy that none of these apply and can't see any other issues with this, then go for the cavity insulation.
> Also quoted £700 to raise my existing loft joists by an additional 50mm, bringing them to 150mm, and then boarding with 18mm insulating board; he thinks this will give equivalent total insulation to 250mm of quilt.
Not sure what what you mean by this, 18mm board sounds like chipboard - is he talking about 18mm chipboard with 150mm of insulation bonded to the back of it? Do you need a solid deck for storage? if not you could just lay the equivalent insulation in between and on top of the joists without increasing their depth. If you have a shower room or otherwise lots of moisture on the top floor you should install a vapour barrier below the new insulation so that moisture doesn't condense inside your roof void (or inside your joists even). There are a few ways to do this:
1) Apply 2 coats of drywall sealer to the ceiling below (although this presumes you are re-decorating)
2) put a vapour barrier below the insulation (i.e. visqueen sheets with taped joints)
3) use insulation that has a vapour barrier fixed to the bottom of it (like foil) or is itself of low vapour permeability (generally any closed cell foam)
no.2 is probably the easiest. Also is the roof void well ventilated?
1
In reply to Jamie Wakeham:
Cavities between walls are there to keep the wet out; if you fill them, then the inside skin of the of the wall is likely to get damp. See http://www.askjeff.co.uk/category/cavity-wall-insulation/
(It would be worth buying a cheap smartphone endoscope off amazon for £10, to check in-case the cavity wall is already partially insulated with boards retained to the inner skin; 1986 - I'd expect it to have been. The blocks used on the inside skin may however be 'thermal' - this was considered adequate in that era.
It's really important to understand vapor barriers, and where the condensation point will be, in whatever you finally go for. Wet roof timbers will rot away in less than 10years, & saturated insulation in (former) cavity walls will make the inner skin wet/ damp & mildewy.
Cavities between walls are there to keep the wet out; if you fill them, then the inside skin of the of the wall is likely to get damp. See http://www.askjeff.co.uk/category/cavity-wall-insulation/
(It would be worth buying a cheap smartphone endoscope off amazon for £10, to check in-case the cavity wall is already partially insulated with boards retained to the inner skin; 1986 - I'd expect it to have been. The blocks used on the inside skin may however be 'thermal' - this was considered adequate in that era.
It's really important to understand vapor barriers, and where the condensation point will be, in whatever you finally go for. Wet roof timbers will rot away in less than 10years, & saturated insulation in (former) cavity walls will make the inner skin wet/ damp & mildewy.
In reply to Jamie Wakeham:
Thanks for replies, all - incredibly useful. To try to answer a few questions:
The house feels cold in the winter, especially the ground floor, and hot in the summer, especially on the top floor. I had hoped that 6kW of solar panels would mitigate the latter (thinking that if I'm diverting 6kW of solar energy away, that's got to keep things a little cooler), but I'm not really noticing much of a difference!
It is dry as a bone, though. It's in a depression and very well sheltered from pretty much every direction. The render seems in good condition and I have to roof looked at when the PV went up so I'm reasonably confident there's no water ingress to the cavity. The most used shower is on the middle floor - currently no fan to vent it but that's coming soon.
The cavities are definitely empty; he drilled and checked with an endoscope. It's common knowledge that nothing on this development got cavity insulation when built, so I wasn;t surprised, despite the age of the house.
I do want to use the loft as storage space - he started by quoting for just cross-laying quilt insulation, but I need that area boarded. No idea what type of board he's specificying so will go check that. I know I could DIY this (did in the last place, but I knew I was leaving soon so wasn't taking quite so much care) - I'd rather pay to have someone do it right. And be available to complain to if it goes wrong!
It looks like the grants are intended for people in receipt of benefits, or in deprived areas, which is fair enough.
Toccata - have I got me a cross-forum stalker..? I'm fairly sure I've not asked about that here! But no - just had a chat with Celotex about insulating that space, so should be going ahead soon.
Thanks for replies, all - incredibly useful. To try to answer a few questions:
The house feels cold in the winter, especially the ground floor, and hot in the summer, especially on the top floor. I had hoped that 6kW of solar panels would mitigate the latter (thinking that if I'm diverting 6kW of solar energy away, that's got to keep things a little cooler), but I'm not really noticing much of a difference!
It is dry as a bone, though. It's in a depression and very well sheltered from pretty much every direction. The render seems in good condition and I have to roof looked at when the PV went up so I'm reasonably confident there's no water ingress to the cavity. The most used shower is on the middle floor - currently no fan to vent it but that's coming soon.
The cavities are definitely empty; he drilled and checked with an endoscope. It's common knowledge that nothing on this development got cavity insulation when built, so I wasn;t surprised, despite the age of the house.
I do want to use the loft as storage space - he started by quoting for just cross-laying quilt insulation, but I need that area boarded. No idea what type of board he's specificying so will go check that. I know I could DIY this (did in the last place, but I knew I was leaving soon so wasn't taking quite so much care) - I'd rather pay to have someone do it right. And be available to complain to if it goes wrong!
It looks like the grants are intended for people in receipt of benefits, or in deprived areas, which is fair enough.
Toccata - have I got me a cross-forum stalker..? I'm fairly sure I've not asked about that here! But no - just had a chat with Celotex about insulating that space, so should be going ahead soon.
In reply to Jamie Wakeham:
Yep, over from W-P (although started here first). Hope you enjoyed the wine I sold you (and sent to the wrong place...). Starting a similar project myself funnily enough but going with active air-humidity management.
> Toccata - have I got me a cross-forum stalker..? I'm fairly sure I've not asked about that here! But no - just had a chat with Celotex about insulating that space, so should be going ahead soon.
Yep, over from W-P (although started here first). Hope you enjoyed the wine I sold you (and sent to the wrong place...). Starting a similar project myself funnily enough but going with active air-humidity management.
In reply to Jamie Wakeham:
>> Also quoted £700 to raise my existing loft joists by an additional 50mm, bringing them to 150mm, and then boarding with 18mm insulating board; he thinks this will give equivalent total insulation to 250mm of quilt.
you don't need to be a DIY professional to either over batten (on top like for like), or counter/cross batten (at 90degrees for load sharing). Then board over the top.
Beware of fancy insulating board(compressed foams & foil backed etc.) that is not breathable, it will give fantastic insulation values, but could cause condensation and rot in the long term if used in the wrong places.
Price wise, depends how big the loft is, how big the hatch is etc.. (shorter lengths, more cutting and faff ). If you don't use the loft for storage, then just fill it yourself with standard insulation, no foil backing etc.. 100mm layers, one on top of the other, overlapping the joins.
>> Also quoted £700 to raise my existing loft joists by an additional 50mm, bringing them to 150mm, and then boarding with 18mm insulating board; he thinks this will give equivalent total insulation to 250mm of quilt.
you don't need to be a DIY professional to either over batten (on top like for like), or counter/cross batten (at 90degrees for load sharing). Then board over the top.
Beware of fancy insulating board(compressed foams & foil backed etc.) that is not breathable, it will give fantastic insulation values, but could cause condensation and rot in the long term if used in the wrong places.
Price wise, depends how big the loft is, how big the hatch is etc.. (shorter lengths, more cutting and faff ). If you don't use the loft for storage, then just fill it yourself with standard insulation, no foil backing etc.. 100mm layers, one on top of the other, overlapping the joins.
In reply to MG:
+1
> Have a google about condensation problems with loft insulation. If you overdo it, or do it wrong, you can end up with damp timbers that may rot and be *very* expensive to fix.
+1
In reply to Toccata:
Aha - now I know who you are! The NSG, especially, was lovely (think I still have one left). Haven't broached the Pomerol yet.
Thanks to all - I'm now equipped with a lot more questions to put to potential installers.
Aha - now I know who you are! The NSG, especially, was lovely (think I still have one left). Haven't broached the Pomerol yet.
Thanks to all - I'm now equipped with a lot more questions to put to potential installers.
In reply to Jamie Wakeham:
You could consider insulating the walls externally ...
https://www.backtoearth.co.uk/products/udireco-wood-fibre-insulation-boards...
It's something I'm considering, if I ever get enough cash to do it!
You could consider insulating the walls externally ...
https://www.backtoearth.co.uk/products/udireco-wood-fibre-insulation-boards...
It's something I'm considering, if I ever get enough cash to do it!
In reply to springfall2008:
It's not government grants, it's a government obligation on energy companies to do this work. So the likes of Npower and British Gas etc are paying for it (and obviously we're paying through our energy bills).
OP: If your house was built after 1986 you're unlikely to get subsidy as the EPC will almost certainly assume cavity wall insulation is in place and therefore no notional carbon savings would be available to the funder by doing the work. However, if this hadn't been the case then you could've been eligible as insulation funding (for loft and walls anyway) is available to all households regardless of income. Can't help with the quote (though it sounds reasonable if you're getting bead done with a lance) but thought it was worth clearing that up in case anyone else read this who might want energy saving work done to their house since by the end of this year a lot of the funding is going to dry up and not be available any longer.
It's not government grants, it's a government obligation on energy companies to do this work. So the likes of Npower and British Gas etc are paying for it (and obviously we're paying through our energy bills).
OP: If your house was built after 1986 you're unlikely to get subsidy as the EPC will almost certainly assume cavity wall insulation is in place and therefore no notional carbon savings would be available to the funder by doing the work. However, if this hadn't been the case then you could've been eligible as insulation funding (for loft and walls anyway) is available to all households regardless of income. Can't help with the quote (though it sounds reasonable if you're getting bead done with a lance) but thought it was worth clearing that up in case anyone else read this who might want energy saving work done to their house since by the end of this year a lot of the funding is going to dry up and not be available any longer.
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