What improvements are people going to make to their insulation ? I have some areas of my loft that do not have 270 mm so that’s an obvious place to start, but should I go higher than 270 mm ?
My RetrofitWorks survey suggested finding out if the cavity wall insulation done some years ago was patchy or had slumped, is anyone else going down that route ?
How about an extra internal wall insulation. Then there’s draught proofing… blocking the unused fireplace, the list is long...
As far as I’m aware, 270mm is probably as much as you’re likely to want unless you’ve got a house which is really bad at leaking absolutely every bit of heat and is a constant iceberg as a result!
It’s quite common advice to consider blocking up or removing fireplaces that you’re no longer using. I’d also agree with this, as long as it’s done properly - but you’d probably want to have the chimney swept out first because you won’t be able to later. Given that fireplaces have said chimneys which can let heat escape with no real control, it’s not worth keeping it open if you’ve decided to stop using the fireplace.
Please make sure you’re certain first though! Undoing something like that is not easy or cheap.
As with everything, it’s often down to what works best for you. If the cavity wall insulation is in good shape and you’ve already got 270mm loft insulation and you’ve got double-glazing on the doors/windows… You’re already doing pretty well!
Thanks. I think we’re pretty safe having the fireplace blocked up, we’ve lived here 18 years and never used it! Our energy rating from RetrofitWorks is 53E - the biggest culprit being our gas fired warm air heating. I’d say the house may well be a constant iceberg unless that’s running 
.
Hi 
If we’re talking about glass-fibre insulation then you probably won’t gain anything by going deeper than 250mm. The crucial bit is how it gets fitted where it dips down into the eaves. Have look at this diagram, helpfully supplied by BRE:
Notice how the insulation roll doesn’t stop at the batten holding the ceiling. It continues right over the wall-plate and down to meet the cavity-fill (if present).
The diagram isn’t completely accurate because it’s the wall plate (my red label) which supports the rafters rather than there being a gap as shown above.
Nevertheless, you will also note the critical gap for air to pass into the attic space and prevent condensation gathering on the cold roof timbers. Without this they will rot!
I have never seen a professional insulation company get these details correct. They normally use the most junior team member to crawl into the narrow angle and prod the insulation with a piece of wood. That’s not effective, and you will end up with cold corners on the bedroom ceilings which eventually grow black mildew.
I wouldn’t get rid of any warm-air ducted system. Just decommission the gas input to it.
I actually installed a warm-air ventilation system when I refurbished our 1937 farmhouse. It takes stale air from bathrooms and kitchen, passes it through a heat exchanger and pushes fresh warmed air back into living spaces.
I supplement the heat by having a small “radiator” to further raise the temperature of the air before it gets piped to bedrooms and sitting-room. You could do the same trick by taking heat from the Heat pump. I’ll explain in more detail later if you want.
My house now has a warm-roof construction.
We took off the slates, added 50mm phenolic insulation board and then used counter-battens to position a new slate roof on top.
Following the outside part of the job, I used 75mm-thick phenolic boards between the rafters, giving us 125mm overall.
It’s called “warm roof” because the rafters, purlins and trusses are now within the insulation envelope of the house. They don’t get cold, so no condensation forms and thus they can’t rot.
Large quantities of B-grade phenolic board insulation are available from Seconds & Co who will deliver by lorry when they have other orders in your area. Some sheets have damaged edges which can be cut off, and some are of uneven thickness. But they are very much cheaper than you could get elsewhere.
I am very much a hands on renovator, and don’t like employing contractors if I can possibly avoid it. So any suggestions I make are from real first-hand experience.
Hi
I was that junior team member years ago when I installed the insulation 
and I think I did poke it into place with a stick… claustrophobia will now prevent me going back there but everything seems okay regarding condensation and mildew. I’m replacing the insulation in the middle part of the loft having fixed a LoftZone platform so that I can easily access the new equipment. I’m not convinced the ASHP will give us enough heat over the coldest winter days so hanging onto the old gas system. I assume the rules of the trial mean I’m not allowed to run it but I don’t want anyone to decommission it - for one thing I’ll get it serviced during the summer and obv it’ll have to work for that! I did think about having the ducts sealed by ‘Aeroseal’ to improve its efficiency. Expensive, unless I can find neighbours who’d like that done too. I like the idea of the ventilation system with heat recovery so I’d definitely want to keep it as intact as possible until I decide what’s required.
This shows the area needed for access to the new equipment now. The cold water cistern was previously high up on a platform beyond the carpeted area, the original cement asbestos tanks are now sitting on a celotex insulated platform out of the way. LoftZone beams ready for boards.
That all looks good
Seeing those deep rafters makes it very tempting to go for a warm roof construction!
The parts aren’t expensive. But the real costs are the scaffolding and labour to put an external layer of insulation under the tiles/slates.
Your hot-air ducting looks well insulated already. You could add to that, but I’d hesitate about getting in contractors to do a “professional job”.
I’m not tempted !!
The silver wrapped ducts are the ones I did some years ago, the less accessible ones and the diagonal one in the distance are just covered in the original glass fibre and paper wrap with my extra layer of 100 mm loft insulation. I intend to get some Foil faced Ductwrap to redo the diagonal one. The Aeroseal would be to seal any air gaps, I’m sure there must be gaps which I’m not going to search out, some of the furthest registers hardly have any heat coming out of them. But of course if the ASHP works okay I don’t need to worry!
Even if the ASHP works OK, I can’t see how the configuration being installed is financially viable. You’re going to need that insulation to be top-notch if you want to get the COP above 4.0
When I added warm air ducts most of the pipes were run in the attic, which is within the insulation envelope of the house. So I bought lightweight/cheap plastic components from BES and taped them together. I applied a foil bubble-wrap (400mm wide) around the outside and held it place with aluminium tape.
If there were any minor leaks in the plastic pipe joints, they had little effect because the taped insulation layer also prevented escapes.
If I were to tackle the same task in your “cold” attic, I’d employ the same approach, but use a much higher grade foil-insulation, such as Actis’ Triso Super-10. That’s equivalent to about 100mm of conventional mineral-wool insulation.
Well the ASHP is running a new set of radiators, so I only need to worry about the warm air ducting for the winter months. I know it goes against the green credentials to use gas for that but I suppose I have to weigh up the cost of improvements v price of fuel.
So assuming I get the loft to something better than it is now (including the insulation crushed by the plumber putting in the radiator pipework
), and have the fireplace blocked up, what would be the most cost effective thing to tackle next ?
Do you cavity walls
And, if so, do they have insulation filling that cavity?
What construction has been used for the bungalow floor? Solid concrete slab with no insulation below it?
Yes, and yes.
Retrofit suggested the cavity wall insulation may have slumped so I could get a thermal image done to check that, have it removed if it is and refilled…. seemed a bit hit and miss as how would I know a second version would be any better ? Do you have any experience of that ?
The floor is very cold, scored badly on the report but I have hardwood flooring, 3 bedrooms carpeted, and big rug in sitting room. I wondered about heavier grade underlay, I’d like wool but we have those blasted carpet moths which would have a field day !
The price suggested to get to the ‘After’ condition is about £30000.
OOOOO I love a good loft image.
I can see that Hydrosam is seeing this topic so I won’t tag them, but other heating trialists, just a quick tag to make sure you’re aware of this thread - it might be useful!
The key with a cold attic is to ventilate it well.
Re the loft insulation and ventilation
please ignore missing board from my garden room !
Your posts were picked up as spam for some reason,
*Correction:
And I’m just copying stuff across from the tariff topic:
When you say ‘apart from the additional insulation works’ my installation is just the ASHP, hot water cylinder and new radiator system, any insulation and improvements in that area will be at my own expense, which is why I’m keen to find out more about where and what to spend it on.
and then:
it seems the budget was all used up unfortunately. I do have a house full of expensive kit though !
I must be in the wrong job.
Could I get paid for filling customer houses with expensive kit and then charge even more to have them undertake renovations required to make that kit viable?!
Thanks
However, if the problem with ramming loft insulation into the soffit/eaves (re
Adding soffit vents is simple and cheap. These cost 35p each from Toolstation
Vent tiles within the roof are no good unless they penetrate the felt layer. How are you going to do that without risk of rain entering should a tile break in future?
And here’s a pack of 50 inter-rafter ventilation trays from the Roofing Superstore at just under £70
These trays enable you to implement the diagram I posted earlier.
Thanks ! that’s very helpful.
Whilst I’m busy name-dropping, there’s a massive national wholesaler called Sheffield Insulation Group (SIG) with a wide range of products.
What few people realise is that they sell smaller quantities to end-customers under the trading name Insulation Express.
So
Be aware that SIG often make deliveries using their own fleet of enormous lorries that have a fork-lift truck hanging off the back. So be prepared to simply have a pallet dropped off for you to unpack!
As
Some even have underfloor heating pipe tracks routed into the insulation boards. Here’s one from Uponor, called Siccus, available in 15mm and 30mm varients:
If you’re going to add insulation beneath a new floor surface, then it makes sense to install a mechanism which also allows future upgrades to UFH. This uses water at lower temperature than radiators, and hence the Heat pump operates more efficiently.
I must however point out that running an UFH system like this during the Trial would interfere with the calculations they require for their report to BEIS.
The part of the original report which I found hard to comprehend was to increase the insulation, consider triple glazed windows - and then to increase the ventilation. Seems a daft amount of expense to me and I won't be changing my windows.
No account yet? Create an account
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.
