Viewing 35 posts - 1 through 35 (of 35 total)
  • House insulation questions
  • swoosh
    Free Member

    our 1960s link-detached house is chuffing cold and loses quite lot of heat over night and during the day when the heatings off so i’m thinking of putting some loft insulation in over xmas period as we only have about 50-75mm at the moment. going to put in 200mm extra laid on top of existing.

    Does it make that much difference? will we notice difference in temperature in the house or just to our monthly bills?

    How about cavity wall insulation? How much does that cost to get done and how long til we get our money back? will that make a measureable difference to inside ttemperature? are there any issues with cold bridging and damp that anyone knows of?

    please advise a cold and tight fellow STWer!

    Liftman
    Full Member

    Check if the council/goverment are doing any rebates in your area, we got our cavity wall insulation done for £99.

    You definately want to put the 200mm extra in your loft, you will notice the difference.

    sharki
    Free Member

    At least 300mm seems to be recommended now for lofts.

    Simple things like keeping doors closed can help in retaining heat and used lined curtains.

    Mixed results from cavity wall insulation. Some say it makes a difference some don’t.

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    rightplacerighttime
    Free Member

    Extra loft insulation is an absolute no brainer – do it ASAP, but don’t block up the eaves as you need ventilation above the insulation or you’ll get condensation/damp/rot. Although you can get vents to poke through your sarking between the tiles/slates and/or ridge vents.

    Cavity wall insulation is a cause of debate. It will make a big difference to keeping the house warm, but may cause damp problems.

    convert
    Full Member

    Does it make that much difference? will we notice difference in temperature in the house or just to our monthly bills?

    It should but how the difference manifests itself will be dependent on who is in change of the thermostat! Your house will either be warmer for the same amount of gas or use less gas to get to the existing temperatures.

    We did the same to a similar house and whilst not night and day, it did make a difference. The only thing I would say is make sure you don’t cover the vents around the edge that allow air to circulate or you will have a very wet loft.

    A decent central heating controller that allows a good level of control to the temperature throughout the day/week and thermostatic valves for your rads should also be on your shopping list if not already fitted.

    fisha
    Free Member

    do the loft asap. generally, the current way of doing it is to run the insulation along between the rafters, then run a second layer in the other direction at 90 degrees.

    It makes a big difference, and as already said, leave a gap. 2″ is the minimum apparently.

    Cavity wall insulation … no personally a fan.

    swoosh
    Free Member

    we’ve got a decent heating control that allows different times for each day of th week and upto 3 ‘on’ settings a day. all the rads have a dial on to control heat in that room.

    At the end of a evening the upstairs is noticably cooler than the downstairs where we’ve been all evening so maybe loft insulation will make biggest difference here?

    I think current new house building regs say minimum is 270mm so guess i’ll be somewhere in the region of that once i’ve put 200mm more down.

    I only keep a few things in the loft so wont be putting lots of boarding down after, just the size of a door or two maybe, certainly no more than that, so is it ok to keep the insulation in other areas placed between joists and extending above them? or should I get 100mm to lay between joists and 100mm to lay at 90 deg to joists?

    sorry for all the questions but i’ve never had to know much about insulation before.

    marky-p
    Free Member

    loft insulation is absolute mustdo. usually the building regs for us is 100 between joists and 150mm over top.

    as for cavity wall, dont personally agree with it. think it causes more problems. I have been to a few houses where damp has been a major problem, and the common is cavity wall insulation. The cavity is there to stop damp and cold getting thro the skins of brick work into the house. So when you fill it up it transfers the cold and damp across.

    if your serious about saving heat/energy, then i would seriously recommend getting new windows and doors. You lose most of your heat thro windows and doors.

    also bit of a long shot, but if you can get under the floor, put insulation under the floor. off the ground, hanging from joists.

    Philby
    Full Member

    If you are doing your loft insulation don’t forget to lag your water tank and pipes.

    Cavity wall insulation is one of the most cost effective methods of insulating a home. Cold bridging and damp is only likely to occur if the cavity is not suitable for it, or it is not installed properly. There are many grants around – check your gas and electricity supplier.

    swoosh
    Free Member

    boiler was replaced about 7 years ago by previous owners who didnt put combi boiler in. I dont understand why you wouldn’t put a combi in, aren’t they supposed to be really efficient compared with conventional ones? when this on breaks we will definitely get a combi one. all pipes and tanks in loft are lagged which will save me a job.

    I thought i’d heard somewhere that if you fill your cavity with insulation then the damp has a direct route into the house which is why new houses only have insulation board againt one skin of brick/blockwork to keep a cavity but have it insulated at same time.

    Will be doing our loft this xmas break then. It looks like it will only cost us £30 or so (approx 50m2) for materials plus a day(ish) of work for me. Like people have said, its a bit of a no brainer isn’t it.

    gusamc
    Free Member

    loft insulation as above

    ‘old people’ used to
    – line floor with newspapers (under underlay)
    – thick curtains on windows and doors
    – draught excluders

    franksinatra
    Full Member

    Loft insulation £3 a roll from Build Centre, including delivery.
    Cheap Loft Stuff Link

    When it is that cheap it is hard to justify not doing it. I had to top up my loft and did the whole lot for under £20.

    marky-p
    Free Member

    the strange thing is that the cheaper stuff from b&q etc, isnt suitable for new builds.

    tomlevell
    Full Member

    boiler was replaced about 7 years ago by previous owners who didnt put combi boiler in. I dont understand why you wouldn’t put a combi in, aren’t they supposed to be really efficient compared with conventional ones? when this on breaks we will definitely get a combi one. all pipes and tanks in loft are lagged which will save me a job.

    Don’t come crying on here when your combi breaks and you have no hot water or heating :0)

    Daft (but cheaper) to leave the tanks in though. System boiler + unvented cylinder is “the best” but combi is good for space saving and efficiency.

    We went from no loft insulation to as much as could be put in. 50mm Kingspan above our bedroom for example. Gone from both duvets in winter to the single thin one (not overheating the house but the chimney runs through the bedroom). The house noticeably retains heat upstairs in comparison to how it used to be.

    nickb
    Full Member

    Out of interest, does anyone have any experience of using more solid style insulated boarding to insulate their loft?

    We have very limited insulation now, and want to add lots and also board the loft. 2 options we’re looking at are:
    1. Insulate the the top of the current joists
    2. Add raisers to lift some areas of the the joints to circa 200-300mm
    3. Insulate to that depth
    4. Board over the top

    Or
    1. Insulate the the top of the current joists
    2. Add 4 inches of celotex (or similar)
    3. Board on top

    Anyone tried this? I’m told that 4″ of celotex is roughly equivalent to 8″ of rock wool, but would be good to hear anyone else’s experiences.

    Cheers,
    Nick

    simons_nicolai-uk
    Free Member

    1. Insulate the the top of the current joists
    2. Add 4 inches of celotex (or similar)
    3. Board on top

    This is what we did and it seems to have worked fine. The celotex is only supported by the joists but we were careful to lay crossways and maximise the support it gets.

    It’s probably not the best solution but it retained the loft height and was a lot less work than adding raisers.

    marky-p
    Free Member

    personally we only use celotex in walls, tbh if your planning on puttin down 200 -300mm of rockwool should be enough. if your house has timber kit walls, even insulating them will make a difference. in my house i have domers and last year stripped them and insulated them, did make a big difference up stairs.

    thegreatape
    Free Member

    We had extra insulation put in our loft a few months ago, and it has made a difference. However, when I was up in the loft last week getting some cases down, I noticed how much colder it was, which made me think does the extra insulation increase the risk of the pipes around the tanks bursting? They were lagged when the insulation was done, but still, could that happen now the loft is colder? I’ve just been away for a week, and left the loft hatch open just incase. Obviously that’s a bit wasteful, but anything to avoid the flood we had last Christmas.

    missingfrontallobe
    Free Member

    Our house is relatively new (16 years), but we found a big difference getting cavity wall done & new UPVC windows & doors. Still need to do the loft insulation, and TBH that will probably make more of a difference than cavity wall.

    Might look at this job in the spring ready for next winter.

    Marko
    Full Member

    “the cheaper stuff from b&q etc, isn’t suitable for new builds”.

    So it’s not all the same. I just had some Knauf 44 Combi cut 170mm loft roll delivered by Travis Perkins at £33.16 +vat per pack. This roll covers 8.01 Sqm.

    Hth
    Marko

    molgrips
    Free Member

    Makes a huge difference. We had a thick layer already in our new build and I put two more layers on top. Big difference not only to heat but also sound. Cost £100 or so.

    With regards boarding the loft, I put in a raised floor attached to the rafters. Been a bit of a pain to be honest, I should’ve done more research!

    tomlevell
    Full Member

    Yes Celotex/kingspan installed in our existing part of the roof as space was very limited.
    The main reason for not doing it is it costs far more than 2 or 3 times the depth of rock wool. Also takes longer to fit as it has to be cut to fit between boards.

    theotherjonv
    Full Member

    Very interested in this.

    We have insulation in our loft that looks like hamster bedding / shredded newspaper to the top of the joists. Then the middle ‘standing’ part of the loft (before the eaves get too low) is boarded over.

    I could easily lay insulation myself over the two eave areas, but the boarded bit looks like a faff. I’d assumed I’d have to lift the existing boarding, raise the joists, lay insulation and then replace the boards? But am i reading above that I could lift the boards, cover the existing joist with Celotex and then just relay the boards on top?

    What’s the price difference between (at a guess) 40m^2 of Celotex vs 40m^2 of additional joists and rockwool?

    Helios
    Free Member

    marky-p – Member

    the strange thing is that the cheaper stuff from b&q etc, isnt suitable for new builds.

    I was under the impression that you’re just not allowed to use it in new build because it has been subsidised and the point of the subsidy is for it to go to older properties.

    tomlevell
    Full Member

    Shredded newspaper is good. They fill timber framed housed walls with the stuff. You may find you have it under the boarded section.

    If not then you can cut celotex to fit inbetween the joists (not on top) or just fill it with rockwool.

    Price difference = Dunno. Lots.

    swoosh
    Free Member

    I’m wanting to keep a couple of small areas boarded out for light storage so i’m hoping to put boards directly on to the joists in these areas (I realise this will reduce thermal insulation but i’m willing to take that reduction for the sake of this small area of storage) as i cant be bothered with raising joists etc.

    I’ve found some cheap 200mm thick Knauf insulation from B&Q so was hoping to lay that between joists but it says it is for laying above joist level, surely it wont matter if it lay it between joists, will it? After all it’s going to be on top of the existing insulation so wont be in direct contact with the ceiling boards. I realise it will extend above the joists but if I lay it between the joists at least i’ll be able to see where the joists are when i have to go up there.

    mountaincarrot
    Free Member

    It’s well worth extending the joists. I’d consider just edge on plywood or Sterling board screwed to the joists. Would be a bit wobbly but if you add a few diagonals also, then a loft floor wouldn’t be out of the question.

    Insulate the hatch as well. Cellotex or a polythene “pillow” filled with glass to stuff up before you close it. And seal every gap to the house.

    Munqe-chick
    Free Member

    Haven’t read the rest of the thread other than OP post but as Liftman said see what offers the council have on. we recently had out loft insulation doubled for £99. A mate did his own, it cost him £89 for the materials and about 2 days of back breaking work! They were also doing cavity wall insulation for £99 but we didn’t need that. Oh and we noticed last night that bleeding the radiator suddenly increased the heat 100% in the bathroom 😳

    swoosh
    Free Member

    my loft is 48m2 and already has 50-75mm of insulation so I only need another 200mm to bring it up to modern standards, £3 a roll that covers 5.5m2 so thats less than 9 rolls = £27. I’d rather pay £27 than £99 for the same stuff and do it myself. If it was cavity insulation or something you special equipment for then i would get them to do it but a saving of over £70 is worth it in my book.

    But yes, bleeding radiators will help heat a room up 😉

    foolishmiracles
    Free Member

    Anyone know anything bout insulation and electricity cables? I live in a bungalow and there are allsorts of electricty cables to the lights etc lying on top of the joists.I cant find much information on it but I believe it isnt a good idea to lay insulation over cables? Also we have a number of spotlights and obviously you cant lay insulation over them.Has anybody used “hoods” over them?Or what have you done? Cheers

    trb
    Free Member

    We had cavity wall insulation installed a couple of years ago in our 1970s built house and it increased the “first thing in the morning after having the heating off all night” temp by 2 degrees C. It has also reduced the severity of a couple of small damp patches

    swoosh
    Free Member

    Also we have a number of spotlights and obviously you cant lay insulation over them.Has anybody used “hoods” over them?Or what have you done? Cheers

    I’ve not done this myself but i believe if you had a 200mm diameter tube placed around each light you can then lay insulation around the tube – but not over it so the lights heat doesnt set the insulation alight.

    Haze
    Full Member

    We have loose fill in our loft, adding a layer of Rockwool (as soon as I can be arsed) at either end and boarding the the middle run for access.

    Cavity walls are being done first week of the new year, costing us £149 for the whole lot.

    Can anyone on here advise on whether I’ll need to add a core vent for our coal fire?

    Guy who did our survey wasn’t sure and I’d like to get it sorted myself before they come if it’s needed. There’s already a floor vent in the corner of the room and an air brick, don’t want to be drilling more holes if it’s not necessary…

    wisepranker
    Free Member

    We’ve just had the cavity walls insulated in our 1950’s maisonette last week and the difference is pretty spectacular.
    Well worth the £120 that it cost. I’d recommend it to anyone!

    tomlevell
    Full Member

    Can anyone on here advise on whether I’ll need to add a core vent for our coal fire?

    You’ll need some sort of permanent opening. Probably 100cm2 but needs to be checked on what exactly.
    If you have a ventilated floor this can generally be achieved with a floor grille.

    Otherwise through a wall look for a “black hole ventilator”

Viewing 35 posts - 1 through 35 (of 35 total)

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