Old houses: Energy & insulation refits

[dspp]

Those of you dissing solar panels in northern countries clearly don't own much solar. I do and I could run 11-months of the year off my little 4kW array, both for my house and to do 10-12,000 miles per year in an EV (inc any Tesla) except for the minor matter of not having off-street parking in my place (ok, that sucks).

Perhaps you are not a tenant in a 2000sq ft Edwardian detached house. I assure you, the 70kWh (about £10 worth) of power generated in March by our 4kW solar installation does not go very far towards paying the bills!

[EDIT: the point I am making is that not everyone's installation is ideal, and you may not realise how efficient your house is compared to many out there, particularly larger, older properties. A lot of solar work in this country is being driven by government bungs, not science.]

GS

No I am not in a large 2,000 sq ft (=185m2) Edwardian pile. I am in an earlier (1900, Victorian, conservation district) property of 210m2 floor space, on three floors, so ground space is 70m2 footprint. I am unsure if you are talking footprint or floor space, and I don't know how many floors you have. If you give me those numbers I can work out the equivalency of our two properties and calculate what is reasonably possible in energy terms for you.

The reason my older property is so energy efficient is because I have done a few very basic cheap things to make it so. Things that pretty much anyone in similar 1840-1940 properties could do.

I am currently, year-by-year, working through a series of projects at my girlfriend's place (1840, grade 2 listed, and about 400m2 + footprint and 800m2 + floorspace*) to get her property in a fit state for the next 100-years. It really is / was a pile. That will probably involve about 12kW of solar by the time it is completed, but at the moment it is at the 4kW level and most of the effort is going into insulation as each room or section is tackled. It makes a very real difference : to her expenditure on oil & elec bills; to her comfort levels; and to the value of the property. So I know about the reality of dealing with older UK properties, large and small.

regards, dspp

Would very much appreciate a few tips from your experience in a clean thread, possibly on the DIY board. Property has ground and first, actually closer to 2500sq ft double glazed thoughout, standard brick construction, tiled roof, insulated loft, four external doors (two traditional, two double-glazed), fireplaces, both DHW and traditional wet radiator system driven by air-source heat pump, with aga in winter months (now off), no zoning. Elec. approx £1700 per year, oil £800 (guess). Bearing in mind landlord has to agree, where do we start?


GS

**** this is a repost of something GS wrote that is best put here, but Modding rights are stretched too much ****

[dspp]

GS,
Do you mean that it has two floors, each of 2,500 sq ft (=250m2) totalling 5,000 sq ft. Or is it two floors each of 1,250 sq ft (=125m2) totalling 2,500 sq ft ?
regards,
dspp

[GoSeigen]

GS,
Do you mean that it has two floors, each of 2,500 sq ft (=250m2) totalling 5,000 sq ft. Or is it two floors each of 1,250 sq ft (=125m2) totalling 2,500 sq ft ?

The latter, and I should add that we set the heating (thermostat upstairs in hall) to about 16º for two hours in the morning and about five to six hours in the evening. We live rurally so no gas mains.

I know one thing we can do immediately is draft proof the two standard doors and do something about the chimneys, but have not yet investigated how best to do these... Not sure how much difference it'll make as there is a hell of a lot of external wall/window/roof, and the house still needs to breathe, right?

GS

[dspp]

Let me do some sums and I'll get back to you.

Old houses of this age are so draughty that, unless you are being excessive with sources of humidity, you don't need to worry about oversealing them provided you also keep them at a decent temperature. If only that were possible ....

regards, dspp

[Slarti]

I know one thing we can do immediately is draft proof the two standard doors and do something about the chimneys, but have not yet investigated how best to do these.

Because we hardly ever use the fire in the living room I invested in a Chimney Sheep https://www.chimneysheep.co.uk/
Once I'd got it properly fitted, so there were no drafts in any corners, we noticed a reduction in gas usage. I think it took a winter and a half to pay for itself.

Just a thought.
Slarti

[dspp]

GS,
Do you mean that it has two floors, each of 2,500 sq ft (=250m2) totalling 5,000 sq ft. Or is it two floors each of 1,250 sq ft (=125m2) totalling 2,500 sq ft ?

The latter, and I should add that we set the heating (thermostat upstairs in hall) to about 16º for two hours in the morning and about five to six hours in the evening. We live rurally so no gas mains.

I know one thing we can do immediately is draft proof the two standard doors and do something about the chimneys, but have not yet investigated how best to do these... Not sure how much difference it'll make as there is a hell of a lot of external wall/window/roof, and the house still needs to breathe, right?

GS

OK I've dug out some old numbers for my GF's, plus some up to date numbers for mine. For mine you can ignore the solar as all 90%+ of my solar goes direct to grid. For her these are pre the solar install and most of the recent upgrades and are so a fair guess at where you are now (?). Like you she was running her house cold back then because she couldn't afford it. Like me she now runs it at 20C, but I'll pull out the current situation numbers over the weekend.

I am using £0.14/kWh for elec; £0.57/ltr for oil; and £0.05/kWh for gas. These are not perfect but close enough to be helpful.

MINE = 4 bed 1900 build of 137m2 floorspace
elec = 1040 kWh/yr so 7.6 kWh/yr/m2 = £146
gas = 10919 kWh/yr so 80 kWh/yr/m2 = £546
TOT = £692, so £5.03 per yr per m2

MY GIRLFRIEND = 7 bed 1840 build of 418m2 floorspace
elec = 14,000 kWh/yr so 33 kWh/yr/m2 = £1960
oil = 35,000 kWh/yr so 84 kWh/yr/m2 = £1705 (note there are 11.7 kWh/ltr in heating oil)
TOT = £3,665, so £8.77 per yr per m2


YOU = ????? 1901+ build ??? of 250m2 floorspace
assuming some guesses based on info you have put in your posts
elec = 12,500 kWh/yr so 50 kWh/yr/m2 = £1750
oil = 20,000 kWh/yr so 80 kWh/yr/m2 = £974
TOT = £2,274, so £10.90 per yr per m2

May I suggest you look through these numbers and see if yours are about right. It is important to understand that because that is the beginning for trying to diagnose what to do. However I will warn you that what one does is basically do a major upgrade on a room-by-room basis, and if you are a tenant that is problematic. Basically you put in insulation so that you can shift your temperature from 16C to 20C with no extra running cost. In my case about half the gas is used for cooking and hot water (and I have three adults in a four bed property).

regards, dspp

[supremetwo]

MY GIRLFRIEND = 7 bed 1840 build of 418m2 floorspace regards, dspp

I was going to suggest marrying the girlfriend and moving in with her, but read back that this was a rental.

Is it listed?

If so, there could be significant expense to get consent for any changes.

[dspp]

MY GIRLFRIEND = 7 bed 1840 build of 418m2 floorspace regards, dspp

I was going to suggest marrying the girlfriend and moving in with her, but read back that this was a rental.

Is it listed?

If so, there could be significant expense to get consent for any changes.

Thank you s2, but we are both happy with how we run our lives. It works for us, and the people around us. I get to go to the countryside, and she gets to go to the town We both own our properties, it is GS who is in a rental. I think you'll find from other things he has said that that is through choice.

If you read the thread I have given the listed/protected status. We take care of that, carefully.

regards, dspp

[dspp]

(padding)

GS,

Here you go. I've pulled out data with my GF for the last year and this shows some of the results of the upgrade at her place, i.e. a 17% reduction in running cost excluding the solar. With the solar it is a 32% reduction in running costs. What the running cost numbers don'y tell you is that she used to be shivering in one room, and now she has full use of the (rather large) pile and much happier lodgers and tenants who are easier to keep. Plus eliminated damp issues and so on.

You'll need to look at the table thoughtfully to back out the calcs as I can't put the spreadsheet formatting up. Basically you have four different properties with mine showing something akin to an ultimate target (though I have more I wish to do). Then you have my GF's before, and the current (mid-project) status. Then there is yours as best I can reckon it.

Have a gander and ask any questions.

regards,
dspp

[AsleepInYorkshire]

In all structures there is something known as the dew point. In an external wall if the dew point occurs on the inside of the house then this can cause problems. It can be the case that increasing the insulation of any home could result in moving the dew point to an area in the external walls where you don't really want it.

In addition if you are only able to insulate certain areas of the structure you may create unwanted cold bridging. Apart from the obvious heat loss through this part of the structure it often leads to "pattern staining" which can look unsightly and increase the need to redecorate.

Insulation exists in several forms. But for the purposed of making it simple

1 ) Quilt insulation
2 ) EPS (Expanded Polystyrene)
3 ) PIR (polyisocyanurate)

Generally quilt is the least expensive and provides the least thermal resistance per mm thickness. Next is EPS and finally PIR.

Quick Wins

1 ) 300mm thick quilt insulation in the loft laid between the ceiling joists and cross laid over the top of the ceiling joists. Ensure the roof space is adequately ventilated or it will "sweat" and your dew point may move lower down into the ceiling structure.
2) Draught proofing. Don't underestimate how much this is worth. All modern buildings have to have an "air test" and meet a SAPS rating requirement as determined by the SAPS consultant before it can be signed off by Building Control. In an older property with timber floors you may wish to consider sealing under the skirting boards with to prevent the passage of air from under the floor boards. Look at the other obvious points where cold air can enter the house. For example letter boxes, keyholes service entry points, unused chimneys and external windows and doors.

Can do's but costs may outweigh the gains

1 ) Secondary heating sources such as wood burners or gas/oil fires taking into account the necessary regulations relating to fitting these kind of appliances which can often increase the initial headline price.
2 ) New external doors with insulated cores (usually PIR).
3 ) Underfloor heating. It is available for "retro fitting" in existing homes but I am not sure of the costs and subsequent £/M2 recovery.
4 ) Insulate the external walls. Using PIR to reduce the overall thickness of space lost to the insulation will be expensive and I'm not entirely sure this cost can be recovered. Quilt insulation will help but to achieve a significant increase in the thermal resistance of the wall it will have to be very thick. It will also require new plasterboard and redecoration. If you want pursue this regardless of cost/recovery then you could use a PIR insulation say 50mm thick laid between timber battens and use a PIR lined plasterboard over the top of this. We build large new homes and where we construct rooms in the loft we are required to use an overall thickness of 150mm of PIR which we achieve by partial in the wall PIR insulation and over-boarding with thermal plasterboards.
5) Thick curtains with linings. Probably more of a comfort gain than a cost gain.
6 ) Lift the existing timber ground floors, insulate between the joists and replace with new floorboarding.

AiY

[GoSeigen]

YOU = ????? 1901+ build ??? of 250m2 floorspace
assuming some guesses based on info you have put in your posts
elec = 12,500 kWh/yr so 50 kWh/yr/m2 = £1750
oil = 20,000 kWh/yr so 80 kWh/yr/m2 = £974
TOT = £2,274, so £10.90 per yr per m2

May I suggest you look through these numbers and see if yours are about right. It is important to understand that because that is the beginning for trying to diagnose what to do. However I will warn you that what one does is basically do a major upgrade on a room-by-room basis, and if you are a tenant that is problematic. Basically you put in insulation so that you can shift your temperature from 16C to 20C with no extra running cost. In my case about half the gas is used for cooking and hot water (and I have three adults in a four bed property).

regards, dspp

Updating the above:

GS = 5 bed 1910 plus later additions build of 250m2 floorspace
assuming some guesses based on info you have put in your posts
elec = 10,000 kWh/yr so 40 kWh/yr/m2 = £1400
oil = Approx 1500ltrs @ 52p/ltr


Looking at my own spreadsheet, my earlier elec cost was based on 16p/kWh.

Your spreadsheet figures look pretty low. Can't imagine achieving close to that without fairly major insulation work throughout, but interested in where significant easy gains are to be had. Considering fitting smart thermostatic valves; there are no thermostatic valves at present. Maybe not worth it?


GS

[dspp]

Your spreadsheet figures look pretty low. Can't imagine achieving close to that without fairly major insulation work throughout, but interested in where significant easy gains are to be had. Considering fitting smart thermostatic valves; there are no thermostatic valves at present. Maybe not worth it?

GS

There are no significant easy gains to be had.

If you look at my spreadsheet figures for my own property, that is the high end of what proper passivhaus construction would deliver, i.e. my house barely meets passivhaus levels even after the efforts I have made. Unfortunately in the UK the improvements in BREEAM building standards were nobbled by the Conservatives under Cameron in the era of "cut the green crap" when (as usual) they allowed their mates in the construction industry to overide the technical & economic recommendations of the relevant experts. So we can do much better than I am achieving, these are not really good at all.

My house is fairly typical of what can be achieved as a result of careful thoughtful but low cost work on a period property. If you do it all-in-one-go then it would be a very expensive project. If, like me, you take the approach that each time you work on an area of the house then the additional expenditure is trivial. So when I replaced the roof on the collapsing lean-to and incorporated it into the kitchen I insulated the inside of the exterior wall with 60mm insulated plasterboard, and selected triple glazing rather than double glazing. That's the difference between £8 sheets of PB or £40 sheets of IPB, so maybe £200 extra maximum. And maybe another £300 extra for the triple. Plus I dug out the floor an extra half metre and filled that with insulation as well. So that project probably cost maximum £1000 more than it would have done if I had ignored the issues of efficient & comfortable heat-light-ventilation. When I watch my neighbours up and down my street spending £40k on a typical kitchen refurb, then repeating that every 4 or 5 years, and only ever skim coating and painting, then complaining to me about the running costs of their houses after asking how I do it, then I just figure most are just plain stupid. I'll say that again: some of them come and ask me how come mine is the nicest house in the street and why it is always so warm and light, and never damp, and they can't understand how my bills are so low. Then they go away and ignore what it takes to do it right, and spend excessively on bling. And most jobbing builders and architects in the UK wilfully & repeatedly demonstrate just the same level of ignorance.

We are taking the same approach with my GF's place. The result is decreasing costs (17% or 32% down so far) and increasing comfort, plus increased market value. The additional cost of each project is really trivial, much the same sums as I have given above. That is provided the work is done at the same time as other work in the corresponding area, and provided it is accurately specified in the scope-of-work and/or drawings. There is one exception to this, which is what it costs to do double glazing that the listed buildings people can live with, and there she uses Mettherm (http://www.metthermwindows.co.uk/page/windows) who do not come cheap. But that is a listed buildings issue, not really an insulation issue.

In respect of your place you either have to start tackling the insulation, or you are wasting a lot of your time & money & effort. For example putting in thermostatic valves (either dumb or smart) will just result in them cranking fully open and pouring warmth through the cold uninsulated walls. You have to tackle all six sides of the house, including the floor, if you are to get your heating cost under control. But looking at the figures there is an issue with your electric consumption you need to first understand, then secondly address. You are using about as much electric (12,500 kWh/yr) in your 250m2 house as my girlfriend was in 2014 in her pre-upgrade house of 418m2, i.e. 14,000 kWh/yr. I know that at that time she had electric underfloor heating in one area and that it was cranked to max a lot of the time by the occupants of that area, and was a financial disaster. Yet your usage is even more profligate than that was, so there is something you should consider. In the case of my GF's place, early in our relationship, she put in that elec underfloor heating (and electric hot water) at the insistence of an architect and against my (gentle) advice. She subsequently realised that I had been correct, and we installed a second oil-fired boiler (7kW I think) that now feeds these loads, and removed the heating fuses, and the result speaks for itself in the data. The detail of how best to tackle each issue is case-dependent and feel free to describe the situation and ask for advice. I could write war and peace on each of the projects we have done, but unless you are prepared to go down a similar pathway that may not help you. You first have to identify the root causes of your consumption in a data-driven way, just as with any other encounter with mother nature. Keeping long term records will help you greatly with this. Given your investing etc activity I think this will be easy for you.

For my house my target (excluding FIT income, which distorts things) is to get below £3.00/m2/yr (now £5.03), and for my GF's the target is to get below £5.00/m2/yr (now £7.26) in the next cycle of improvements. That will probably take us 3-4 years as we address various areas. For example I want to finish my bathroom upgrade, which will include insulating its exterior wall, but first I have an old sailing yacht that needs the cash !

I appreciate that you are a tenant, and this may well mean an interesting conversation with your landlord, and may not be worth it. Good luck & don't hesitate to ask on any specific items (or anybody else out there).

regards, dspp

[Itsallaguess]

The result is decreasing costs (17% or 32% down so far) and increasing comfort, plus increased market value.

I think this is a key thing to appreciate when tackling these types of improvement-projects - it's not always, or at least not only, about any potential for cutting energy-costs, it's also about the potential for simply feeling more comfortable in our homes for even what might be existing costs, never mind any potential reductions on those existing costs...

I could write war and peace on each of the projects we have done, but unless you are prepared to go down a similar pathway that may not help you.

..

Good luck & don't hesitate to ask on any specific items (or anybody else out there).

Our gable-end wall is quite a 'cold' wall, and bears the brunt of most of our poor UK weather, be that wind, rain, or often a combination of both...

It's such a large wall that I've often thought about the potential for over-boarding inside with one of the thinner (25mm/30mm) insulated plasterboards, but keep getting put off by the thought of getting the vapour-barrier side of things wrong, and embedding long-term issues into the wall.

If I've got a 'standard' brick cavity wall, with no insulation in it (I would prefer to insulate inside than bridge the cavity wall with insulation), and a standard plaster-on-brick, and then wallpaper-on-plaster construction on the inside face, are you able to describe the process from scratch with regards to the vapour-barrier installation and then over-boarding with the insulated plasterboard, especially with regards to the existing and remaining side-walls (that would not be overboarded), the ceiling (which is normal plasterboard) and the floor (which is wooden floor-boards)? It's often what to do at the 'edges' of the walls with regards to the vapour barrier where things start to look a bit risky to me, but I think this is due to my lack of proper understanding, rather than it necessarily being a tough aspect of the task...

I'd prefer not to use anything wider than 25mm/30mm due to space restrictions, but the installation procedure has always seemed fairly meticulous regarding the vapour-barrier side of things, and it's that single aspect that's putting me off this type of project, which I think would make a huge difference in comfort levels, especially during the winter.

Cheers,

Itsallaguess

[PrincessB]

It's such a large wall that I've often thought about the potential for over-boarding inside with one of the thinner (25mm/30mm) insulated plasterboards, but keep getting put off by the thought of getting the vapour-barrier side of things wrong, and embedding long-term issues into the wall.

To a degree, would this not depend on what is on the outside of this troublesome wall.

I would be inclined to not worry overly if the outer wall is bare brick as the wall should be able to breath quite happily between rainstorms.

That said, all of the internal walls within my cottage (Solid brick walls) are lined with 38mm Ecotherm (insulation + plasterboard) panels - Comes with vapour barrier. Despite the builders being less than ideal, two years in and I've had no problems despite one side of the house being rendered.

U value is down from 2 (Solid brick) to about 0.5 (Solid brick + insulation board) which has made the house great to live in. The gas bill is way down. I rarely close internal doors and following some advice from this board, I've got the radiators in the infrequently used room turned on - Admittely they have TRVs and are turned down low but each room gets a bit of heat each day to maintain temperature.

Regards,

B.

[odysseus2000]

dspp Plus I dug out the floor an extra half metre and filled that with insulation as well.

Do you mean you took up the floor boards, dug down an extra 50 cm & then filled the whole space with insulation?

If so what insulation did you use & does it reach up to the underside of the floor boards?

Regards,

[Itsallaguess]

It's such a large wall that I've often thought about the potential for over-boarding inside with one of the thinner (25mm/30mm) insulated plasterboards, but keep getting put off by the thought of getting the vapour-barrier side of things wrong, and embedding long-term issues into the wall.

To a degree, would this not depend on what is on the outside of this troublesome wall.

I would be inclined to not worry overly if the outer wall is bare brick as the wall should be able to breath quite happily between rainstorms.

That said, all of the internal walls within my cottage (Solid brick walls) are lined with 38mm Ecotherm (insulation + plasterboard) panels - Comes with vapour barrier. Despite the builders being less than ideal, two years in and I've had no problems despite one side of the house being rendered.

Thanks PB, I did forget to mention that the external face of the large wall I would like to potentially insulate is rendered with pebble-dash, so if this is important I'd like to say thanks for teasing this fact out.

Are you able to go into any details as to what you did at the 'edges' of your wall, where your boards came with integrated VB's?

By 'edges', I specifically mean the ceiling, side-wall corners, and flooring edges.

Cheers,

Itsallaguess

[GoSeigen]

Your spreadsheet figures look pretty low. Can't imagine achieving close to that without fairly major insulation work throughout, but interested in where significant easy gains are to be had. Considering fitting smart thermostatic valves; there are no thermostatic valves at present. Maybe not worth it?

GS

There are no significant easy gains to be had.

If you look at my spreadsheet figures for my own property, that is the high end of what proper passivhaus construction would deliver, i.e. my house barely meets passivhaus levels even after the efforts I have made. Unfortunately in the UK the improvements in BREEAM building standards were nobbled by the Conservatives under Cameron in the era of "cut the green crap" when (as usual) they allowed their mates in the construction industry to overide the technical & economic recommendations of the relevant experts. So we can do much better than I am achieving, these are not really good at all.

My house is fairly typical of what can be achieved as a result of careful thoughtful but low cost work on a period property. If you do it all-in-one-go then it would be a very expensive project. If, like me, you take the approach that each time you work on an area of the house then the additional expenditure is trivial.

[...Long and interesting explanation...]

I appreciate that you are a tenant, and this may well mean an interesting conversation with your landlord, and may not be worth it. Good luck & don't hesitate to ask on any specific items (or anybody else out there).

regards, dspp

Thanks dspp, great post, and I have done a bit of reading on the subject over recent years so it doesn't all come as a surprise. It think one thing it told me is that I misread your post on the other board where you said your changes weren't costly and I wrongly interpreted that as meaning they were easy too. I now can see how exactly you achieved the economies so thank you very much for that explanation.


You are aware that we have purchased a commercial property abroad. This is in a location where heating and cooling are an issue and energy costs crucial, so I will be bearing in mind your post when we work on the property. [Additionally it has a problem with noise transmission, so any tips on soundproofing much appreciated.]


For our current property I don't think there is much we can do with the landlord. They are very wealthy and not bothered about energy consumption, just paying the bill whatever it is, and they love gadgets, hence we have an aga, heat pump, oil fired boiler, wood burner, immersion heated DHW tank (which we leave cold) AND solar panels, but minimal insulation and a one inch gap under the front door! (Mitigated by a second internal door.) It's a mess with, for example, the CH controls unable to switch the gas boiler automatically so it is rarely used. DHW has to be heated by the heat pump. And I haven't mentioned the electric fan heaters in the outside play room and a second heat pump in the "gym", neither of which we use much.

So why the high electrical consumption? As I said we heat the entire house for a good 7 hours daily and get all DHW from the heat pump. We have agreed to warm the whole house to prevent damp and mould formation and our rent is correspondingly reduced (LLs said their energy bill was c.£6000pa when they lived here). Is that enough to explain the bills? Here's more: There are very large double glazed windows in the living room and master bedroom. Windows are on the large size throughout. The footprint is L shaped so lots of roof and external wall. The 22mm pipe run from the heat pump to DHW tank is about 30-odd meters and water in the entire run both out and return has to be heated before any DHW heating or central heating occurs. And as you probably know when it's very cold the heat pump has to reverse and pump heat OUT of the house to defrost itself. It's all a nightmare TBH.

Thanks for the points about thermostatic valves. I kind of suspected that myself. Up to now our lifestyle has meant we mostly work in one of the rooms during the day, hence my thoughts about the valves. However, that room happens to be the kitchen area with aga, so we have simply run the aga all winter to provide core heat to the middle of the house (below kids' bedrooms) and kitchen. I wondered if we could get rid of the aga by using the smart valves for heating just this area.

To cap all of the above, the owners didn't want the PV panels on the roof so have put them at the end of the garden, where partial shade drastically reduces their function in all but the middle of the day. You wouldn't believe this but a major culprit is the meter/inverter board, which the installers have positioned where it can cast a reliable shadow on the panels in the early afternoon! Consequently the 4kW panels were only generating about 800W at 3pm (2 hours past zenith) today on a hot, cloudless day.

Bizarre!

GS

[GoSeigen]

It's such a large wall that I've often thought about the potential for over-boarding inside with one of the thinner (25mm/30mm) insulated plasterboards, but keep getting put off by the thought of getting the vapour-barrier side of things wrong, and embedding long-term issues into the wall. [My bold]

This is what worries me about insulating any wall. I guess there are experts who are dependable on this topic...


GS

[AsleepInYorkshire]

If I've got a 'standard' brick cavity wall, with no insulation in it (I would prefer to insulate inside than bridge the cavity wall with insulation), and a standard plaster-on-brick, and then wallpaper-on-plaster construction on the inside face, are you able to describe the process from scratch with regards to the vapour-barrier installation and then over-boarding with the insulated plasterboard, especially with regards to the existing and remaining side-walls (that would not be overboarded), the ceiling (which is normal plasterboard) and the floor (which is wooden floor-boards)? It's often what to do at the 'edges' of the walls with regards to the vapour barrier where things start to look a bit risky to me, but I think this is due to my lack of proper understanding, rather than it necessarily being a tough aspect of the task...

When I started as a trainee QS 40 years ago I was taught that the cavity was there to prevent was ingress which was and still is a problem for many older homes with solid masonry walls. However, modern thoughts are to fill the cavity and crack on with life. My home is 25 years old. I purchased it new. Since purchase some very lovely people have knocked on my door and increased my loft insulation from 100 to 300mm and filled my cavity which was only partially filled with 25mm EPS. Old style polyblocks . Both were free. It may be worth checking for the same in your area. We spend £120/month on electric and gas. It's a modest four bedroom detached home.

I work for a company that build much less modest homes. Starting prices £1.2M. We have just changed to filling our cavities with "SupaBead" from Miller Pattison. It's a blown EPS with a water based glue which sets in place when inside the cavity. It's waterproof and also because it's got small spaces in between the little bobbly bits (highly technical term) it is self draining within the cavity.

I've no experience of blown fibres.

I'd be tempted to look at blown EPS as a solution if it comes at a suitable price. It's thermal resistance is equivalent to dritherm 32 which is a cavity batt system. When blown cavity fill first came out it came with issues where parts of the cavity didn't get filled. These days they drill more holes to ensure complete fill.

AiY

[dspp]

dspp Plus I dug out the floor an extra half metre and filled that with insulation as well.

Do you mean you took up the floor boards, dug down an extra 50 cm & then filled the whole space with insulation?

If so what insulation did you use & does it reach up to the underside of the floor boards?

Regards,

(I'll answer the various other questions from people later, maybe tomorrow)

02000,

My house is a utterly standard Victorian terrace. It genuinely is an average UK house in almost every respect - cost/size/everything. There are various layouts, and mine is that sort that is 5m wide x 7m deep, which means it has a hall & staircase, plus two rooms (one front, one back) in the main run. Then it has the utility block out back that is half the width and contained one room (the kitchen). In the main house section I had a suspended ground floor with the original pine planking on the original joists, some of which were rotten where they went into a wall that was below ground level at the front. Another project was to go into the 1.5m high crawl space and brace up the sagging joists, then to insulate (fibreglass/rockwool) between the joists held up with chicken wire and draft-proof sheeting (Tyvek or equivalent). I tried to avoid the insulation running right up to the external wall in the floorsace as I don't want damp wicking in (that's how the old joists rotted out over a 110+ years), plus I was eliminating a rat ingress point at the time (done !) and I wanted to be able to stop their holes up. I stripped off the old carpet and sanded the boards and varnished them. Fantastic outcome. No draughts, warm, easy. Some of the other houses in my street have 2m in their crawl spaces, some have 1m, and some have concrete floors - it all just depends on the old ground levels.

However the utility block was my kitchen and it had a yard at the side with a lean-to roof etc. That area was 0.5m lower than the road at the front so one stepped down into it, and the whole lot was concrete on earth. It was freezing even in a warm summer day. So I dug out the yard an extra 0.5m more than is normal, put in plastic sheet, then rough concrete, then 0.5m of celotex-style insulation, then some screed. On the old kitchen side I laid 0.2m of celotex to the same level. I had deleted a radiator in jiggling the layout around, so I took the stubs from the radiator and ran a wet loop on top of the celotex (avoiding the area under where kitchen units would go), then more screed, and finally grout & kitchen tiles. The result is that the hot water return from the wet loop heating goes under my kitchen floor and provides a goodly heat store that releases slowly into the house for a few hours after the morning or evening timed heating operates (I just use the old timer/controller, not a new fancy one). The insulation means all the stored energy comes back up into my house and I don't warm the earth worms. It also means my floor warms faster. Lastly I used black slate tiles (cheap ones, very ragged) and that means that in Summer the sun falls onto them (through the triple glazing) and heats them up, and again they act as a thermal store that releases in the evening. Good insulation on the external wall, and in this case also on the party walls, mean that my house doesn't leak heat out of this area.

I did almost the same at my GF's place in her utility room and backdoor area (inc turning a frigid toilet into a nice wet room) when that was 'done' as one of her projects. Once again the marginal cost is an extra 0.5m of excavation & spoil disposal, and a bit of celotex. The wet loop doesn't cost any more than a conventional radiator so that is irrelevant. The effect is fantastic. We also put 100mm thick insulated plaster board on the inside face of all the external walls in this area as we did it. Result, the area of the house that was the coldest/dampest on the north side is now gloriously warm and dry and not damp and mouldy and cost-effectively so.

regards, dspp