MegaSack DRAW - This year's winner is user - rgwb
We will be in touch
We're moving house in a month or so, from a modern 3-bed semi to a slightly larger 1920s 3-bed semi.
In our current house, we've a modern combi boiler and cavity wall insulation, and have got our combined gas and electric bills down to £87 a month.
The new house has had nothing done, and has no wall cavity. We're converting the loft to use as an 'office', so will ram in a bunch of insulation when we do that and we're going to replace the boiler too, trying to either go for solar hot water or to at least be ready to add it later.
We're also going to put in radiator thermostats too, I think.
Is it worth putting in internal wall insulation as we decorate each room? How much does that cost versus what is saved, and does it take much space out of the room?
You can get insulated plasterboard that adds about 25mm to the thickness of the plasterboard. if you are stripping back that much then i would recommend it - have a chat to jewsons - they will be able to advise regarding whats available - insulation isnt my main area - solar is 🙂
is the boiler natural gas or is it oil/LPG? are you thinking of solar in order to save money or are you doing it for the carbon reduction? if its natural gas, and you are doing it to save money - spend the money on better insulation/double glazing/more efficient boiler. if you are a tree-hugger (like me) then solar thermal is a good way to reduce your carbon footprint.
If you can let me know the postcode/direction & pitch of the roof, number of people and type of fuel you will be using, i can do a detailed analysis of what your system is likley to do for you.
The other option would be some Pavatherm wood fibre insulation. You can install it just like plasterboard and then skim over. It's much more breatheable and also carbon zero. It is expensive, but then so is insulated plasterboard.
I'm sure MattOutandAbout will be along shortly to add to this. He works for the company that distributes it.
you need to consider if you are planning on insulating from the inside moving/resizing/replacing all skirtings, window frames, architraves and any cornices etc on all the outside walls you are insulating. 25mm wont really make enough difference to outweigh the cost of the above. you will be up at 50-75mm to achieve the necessary u-values and for the benefits to be seen.
it is only really worth considering if you are prepared to completely strip and redo each room affected (ie its not just decorating)
therefore not really worth it in majority of cases, you are better making sure the loft, floor if poss, windows, boilers are all offering the best performance!
I wouldn't insulate internally myself - you are throwing away thermal mass doing that (anything the other side of insulation doesn't count). This effectively makes your building a light weight structure, which means yes... it heats up fast... but it also cools quickly. Due to heating up fast it also becomes very hot in summer. It's a problem that many modern builds have, and one that is going to become ever more apparent as climate change takes hold.
I would probably insulate the roof big time as a first step, as you say. When you put in a new boiler stick in a hot water tank system (the new ones are fantastic things) that has dual heating coils in it - one attaches to your boiler and the second can be used for solar at a later date (if you are doing it all at the same time you could use a wood burner/pellet stove/woodchip boiler to heat the water rather than a gas boiler, which could work out cheaper to run in the medium term with rising gas prices). The solar hot water systems that attach to the second coil and keeps your tank brimming. Solar can be enough to run all your hot water needs pretty much all year if it is done right, and you don't run too many baths!
Wall insulation - I would be tempted to take off all the render (assuming that is the finish, most 1920's houses tend to be) and whack on external insulation panels. It's a bit of a nightmare but provides you with the U values you are wanting, whilst also retaining thermal mass. The alternative is to pump the cavity full of goo, I think 20's houses tend to be built with a cavity (my one in Stirling certainly was as a neighbour had it done!)
You really want to sort out the airtightness first though, that will make a bigger difference! I wouldn't necessarily replace single glazing with double in this process though - speaking from both an eco-hippy point of view and in energy terms it aint worth it! If windows need replaced then go for it, but otherwise don't bother (you use, surprisingly, additional power with double glazing - it's down to light transmission losses forcing lights to be turned on sooner!)
Oh aye - not sure how worthwhile breathable insulation is on your house - unless it has a breathable construction! If the mortar is cement then chances are there is little point worrying about it! If you have a nice old building with lime mortar then you absolutely want to worry about wall breathability otherwise you wind up with a damp house!
Thanks for the replies everyone.
Sounds like we won't be stripping the rooms back far enough to make interior insulation worthwhile, so we'll just try to get as much as possible into the roof when we convert the loft.
The current boiler is an older gas boiler, on the gas mains, with a hot water cylinder.
We're in the DL1 postcode area and the roof at the back of the house faces slightly east of south. Not sure of the pitch, but here's a photo:
[url= http://farm4.static.flickr.com/3547/3837376885_80341e957c_d.jp g" target="_blank">
Any advice gratefully received.
Just realised that I forgot to say that there are four of us living in the house and, yes, I'm a tree hugger 🙂
*hijacks*
I live in a 1923 property with part flat roof (over the lounge and kitchen). I've insulated the kitchen (ceiling needed replacing anyway), I take it it's a no brainer to do the same to the lounge?
Is there an easy way to calculate savings, what thickness to use etc? (As it's cold and windy here in the Burgh and I live by the sea I am hoping these would be reasonable) and any idea of costs? It's 15' square and it's just a case of pulling down the existing plasterboard, insulating and replacing the plasterboard and coving (wood so re-usable)...I am thinking £150 supplies and a day's labour £150-200?
calculating the savings would be fairly laborious, although i'm sure there a re folk who could do it and most insulation companies would be able to help.
if you are thinking of doing this you would be better going to current u-values, which for a flat roof is 0.2W/sqmK. that way if you sell the house on you are covered from difficult questions. also depending on the build up of the roof you have to watch ventilation and dew points as you can create condensation problems.
your best bet is to decide if you want environmentally good insulation (more expensive) or kingspan/celotex type stuff then approach a manufacturer for their best practice solution. or just speak to someone at keyline for example.
don't know cost wise but at least £500 unless you're doing it yourself
Cheers. Heckler still going strong!
ah you're that Al!
thats great i have only missed it two occasions now! did it build up ok?
It did indeed, the night before an Alps trip on which it didn't miss a beat. The guide (White Room) had an 07 Heckler...it later cracked on the DT by the cages bolts - mine seems OK though 🙂
Oh and is there an easy way to work out what I need to get that u-value (I just stuck 6" recycled stuff up in the kitchen so it may not be worth it...)
and, yes, I'm a tree hugger
Mrs and Mrs miketually at home earlier:
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WOOOF!
glad to hear you're enjoying it! i do think they're excellent bikes maybe not the prettiest but get the job done
sorry didn't see the second part. to achieve the u-value you need if you're using something like kingspan or knauf (rigid foam type) you'll need about 150mm but as you will be putting this in from below you will also need to leave a ventilation space and vent round the fascia (otherwise the roof might rot over time) some of the more natural products such as wool or recycled paper etc don't require the ventilation to be so carefully considered so it might be worth looking at them too (but they are more expensive!) if you let me know what the actual build up is(depth of joists, deck material, roof finish?) i could work something out for you?
Don't spend much time on it....
I was going to do as I did in the kitchen. There are 3" wide joists at 16" intervals, these were 1' high IIRC, then wood and felt above.
Beneath the joists there are perpendicular "battens" - 2" square for the plasterboard to attach to - these support the insulation.
I used this
Can't find tapered plasterboard on B&Q! 😡
i think to avoid major renovations of your roof!! just use the same but put a vapour barrier(polythene sheet) over the lath before you put the plasterboard on or use foil backed plasterboard.
Cheers.
I didn't do that in the kitchen. Am I ****ed? It does "breathe" into the main pitch roof at one side.
no don't worry should be fine!
"wouldn't insulate internally myself - you are throwing away thermal mass doing that"
I know that's the theory, but I haven't found it to be a problem. I had some internal insulation done in our solid-wall house, resulting in the U-value dropping from approx 2 to 0.5. Heats up more quickly, stays warmer, and we haven't found summer over-heating to be a problem.
Or look at external wall insulation,either by battening out using insulation then rainscreen cladding or insulated render,eg:Sto,Weber,Alumasc.Costly though at £75+ per m2 ,applied.
No worries about creating interstitial condensation,cutting down on interior space,and you protect the existing wall.In some areas you can get funding via governmnet initiatives such as CET or CESP.Also look at the NIA website:[url] http://www.nationalinsulationassociation.org.uk/housholder/householder-nia.html [/url]
and [url] http://www.inca-ltd.org.uk/ [/url]
STW has the answer for everything. Thanks guys 🙂
Overheating can be mitigated by a few things - overhangs on the roof, shading from direct sunlight etc. Thermal mass actually works magnificently in practice, not just theory. Spent ages testing all these things for my thesis see... and then moved from a 10 year old rented house that turned into a boiler to a 350 year old house that is superbly cool on hot days (especially downstairs where it has a slate floor!)
I just worry that people get so worried about heat retention and ease to get heat into a house quickly that they ignore possible ramifications of overheating in summer (through solar gain), and then decide to whack air con in to mitigate this new problem, thus rendering the whole exercise utterly pointless! Given how many air conditioning units are sold these days in a country that really has no need for them at all it would seem to be a pretty damn common problem!
Mike
Done a simulation based on the info you gave me - is there somewhere i can send you the PDF output?
just so you know, i work for Graham/Jewsons as their renewable energy rep for Scotland.
Mike