Iceverge

We have a Flymo that cost £522.in 2018. I think it's a rebadged version of the cheapest Husquvarna. I left it out all year and set it to run for an hour or two per night so no first cut dramas or issues with wet grass as it was always short. It will occasionally get stuck in a small hole if it can find it. Every time it did I used to take a spade of earth and fill it in. You'll still need to do the edges with a strimmer or something if that bothers you. I haven't installed it in the new house yet/ever.

Ace. Keep us posted.

Good to hear. Yes seal it to the blockwork. Tape won't work unless you prime it.

That'll be fine. Tidy work. How was fitting the PIR between the rafters?

Ours was cut and welded onsite. Seemed a bit of an overkill TBH.

We have some settlement cracks but I've filled them with sealant and painted over. At least I can see them. Time will tell about the overall airtighess. I would be curious to do another test in 10 years. There have been some suggestions of houses getting more airtight over time. This masonary house only got a worse score after 25 years due to the window seals. https://link.springer.com/article/10.1007/s12053-019-09781-3

Never mind the energy savings or comfort. Airtightness is a big issue with building fabric decay as moist internal air gets carried out on air paths and causes damage to the structure.

Standard blocks are about 70c here inc vat and aerated about €2-3. What's the price difference there?

Airtightness is all down to the junctions. This is common to all build types. If you do a good job of the penetrations and use wet plaster with masonry it's not rocket science. No reason you couldn't do a membrane and service cavity inside a masonry wall like a TF. It'd be a lot cheaper. I was worried about continuity of insulation with ours but the bonded beads filled every single nook and cranny. I test drilled some awkward places to check and had a good scan with the thermal camera too.

Did you consider masonry with EWI?

Why celcons and not normal 7N concrete blocks? The cost of blocks here pre labour is still only about €7/m2 per leaf. Lightweight aerated blocks are about three times the price and only make the difference of a few mm of insulation.

Put some filler in the cracks as best you can and paint it up I'd say. A re-plaster is probably the best option long term.

I wonder if there a novelty factor with ICF that folks like. I remember being enthralled by it when I first saw it. I can build my own house I thought, just like Lego. Then I saw the cost of the blocks and nearly fell over. The trouble is that it's soft on the outside and crunchy on the inside. The wrong way around in my opinion. Much of the lovely "Legoness" goes out the window when you see all the bracing needed and the rebar. The cost of the silicone render made me fall over again. The U Values out of the box aren't often anything special and need a bit extra added. What really puts me off is the risk of needing another 2 blocks and having to wait for them to come from the moon or that awful situation like Insulhub where people lost all the money by needing to pay lots of cash upfront. For now, sticks of timber or blocks/bricks still have lots going for them unless you're building below ground, really need the speed, or have some onerous requirements that necessitate poured concrete.

Tell me more! Any VCL going in? TBH if you are controlling the build yourself a taped external layer of OSB would suffice in my opinion. I'm coming strongly to the opinion that almost all interstitial condensation problems are due to bad airtightness. Nothing wrong with loving! I am a fan myself.

The elevation I drew was one for the bin. I might try again if I get a moment. @AppleDownHow about the adjusted layout? Any thoughts? Maybe tell us more about the style of this conservation area. Some pics might help.

I spent some time yesterday playing with the design and the architect has done an aesthetically nice job really. Although not the cheapest or easiest to build, the stepped sizes of the 3 blocks are quite harmonious. Anything I drew became quite plain in comparison. See this sketch. The original is nicer. Eliminating the chimney might make it tricky to look well although maybe a box dormer or similar to the ensuite/dressing room would make it work. I've been playing with the ground floor. See what you think. Swapping the "cut" in the gable wall will give a nice covered and hidden area outside the utility for any welly boots etc. Getting rid of the small corridor by the backdoor would keep it the same size . Make the utility a long "walk through room". It'll naturally keep itself tidier then and you'll have plenty of wall space for storage/work areas. I would dispense with the separate plant room and put the MVHR, water/ASHP/Boiler in there too. A hoist up drying rack could be included in the vaulted ceiling in the North End too maybe. I've done rationalising of the windows too. Hopefully eliminating a need for too many depleated carbon uranium diamond coated nanotube spacegel skyhooks which architects like to use to hold stuff up. The corner windows are gone too. Mainly because I'm a dryballs, but also they're hard to get right thermally and structurally. Perhaps before you commit to them explore how to build them without serious cost or thermal bridging.

I think someone just wants a twinwall frame.......😂. Are you planning to hang the outer stud over the insulated upstand AKA MBC? TBH for a single story the extra stud outside the framing is a bit wasted in my opinion as you don't have to solve the first floor ceiling band area. If you are committed to the twinwall I would frame the outside wall with 95*44 or maybe 88 or 63mm CLS. 3X2's can be bandy pieces of sh*t. Stand it on a concrete ring beam or strip foundation. Pour your floor with say 100mm upstands. Then put a rockwool style batt between the framing. Joining up to the floor insulation. Then some rockwool batts "freestanding" inside. Then an internal wall with a VCL on the back stood up against the wall to make an insulated service void. This video shows it better. For better sound qualities line the inside with woodwool like Herkalith.

A142 might be a small bit weedy. Maybe a sheet of A252 would be better I would happily place it in the slab as shown. One or two pieces of rebar around the perimeter would make a good job out of it. As shown by the dots below. Frankly it's a lightweight garden room. It ain't goin anywhere MR.

Nothing came close to the cost of a wide cavity block wall for us in 2019/20 except the crappiest PIR filled TF.

Looks fine. Mesh will be easier than Rebar I would say.

Out of interest what is the best way to build a new wall beside an old one in this situation. A gap and some insulation I would imagine but I don't know. Also how best to marry 2 x neighbours dissimilar roofs? A good job benefits everyone re leaks noise maintaince etc.

I'm not 100% following this. Any chance of a sketch? A couple of strategically places pieces of EPS could really reduce any thermal bridging at the wall floor junction.

There's no reference to a sealed vapour control layer here. There's a danger that you will get interstitial condensation. That means that water vapour (like steam, exhaled moisture from your breathing/cooking etc) will be able to pass through small gaps in your wall. If it meets any cold solid surface ( which it will outside the insulation) the vapour will condensed into liquid water. Because it's now cold and a liquid it's stuck there, it can't evaporate. Rot and mould are the result. The Kooltherm would work fine if it was a continuous sheet inside the house but it's not. There'll be holes at every plug socket and gaps between the boards where they're butt jointed as insulated plasterboard. Given you have a U value target of 0.15 I'd do something like the following. Rocksilk 140mm £16.78/m2 50mm PIR with taped joints as VCL £9.05/m2 50mm Rocksilk £5.50/m2 With 50x50 battens £1/m2 15mm plasterboard £5.25 Total £37.58/m2 Or use a layer of 11mm OSB £4.71/m2 and 12.5mm plasterboard instead of 15mm plasterboard. Nice and solid to fix to vs PB alone. Total £40.76/m2 Compare that to the current buildup. 100mm Kooltherm k112 £58.40/m2 37.5mm Kooltherm Insulated plasterboard K118. £ 29.58 Total £87.98. Less labour but twice the price. The free german website Ubakus makes Kooltherma poorer K value of 0.021 than the UK kingspan declaration . I don't know why, but I trust them about as far as I could throw them. Even with a K value of 0.018 you'd be optimistic to hit 0.15 and that assumes perfectly still air in the cavity which would be almost impossible to achieve.

Your Architect has been taken out for lunch by the Kingspan salesman I think. To get a sense of what I mean lets look at some £/R Values or how much insulation costs for a given heat blocking ability. All prices from insulation4less. Please feel free to check my sums but I think it's accurate. Lets take the k112 and something like the Flexirock slabs. So what I hear...... its only £5. What s that between friends!? For your walls of a u value 0.15W/m2K or R 6.6. However that rises to an R value required of 8.25 by the time you account for 10% timber framing. Its a £5.46 hike from the Rocksilk to the Kooltherm per R per m2. So £5.46 X 8.25 x say 100m2 of wall area = £4005 more expensive. Now there are less costs with reduced thickness but nothing like this. We haven't even considered the substantial waste with fitting boards between studs. I think the salesman might have had a week in the Algarve too. Find out if you can return/exchange the K112 would be my first port of call.

Any further details please. Do you have a service cavity. Where is your air control layer? The kooltherm is an unusual choice as it is very very expensive. Normally it would only make sense where you had absolutely no extra space to work with and it was vital you hit a specific U value. In this case you have a U Value of about 0.27 w/m2K. I would take the Kooltherm back to the shop . Fit mineral wool batts between the studs. Then a vapour barrier. Then 50x50 battens perpendicularly with mineral wool infill as a service cavity and then some 15mm plasterboard.