Bitpipe

I'd get a spade then and tell her to get digging What is your plan B, posts on slabs with a timber ring beam & deck?

I was reading log cabin blogs during the summer. A dead flat concrete base was recommended but the cabin itself sat on a ring beam. This firm only supplied wooden floors as an extra over as not everyone wanted them, but they were not structural and just rested on the slab.

Some pictures of my house on this thread - page 2.

I visited one of their sites and considered the whole system for our build but then went TF instead (cast concrete for basement). Was quite impressed with it though. I remember SIPs roofs being very expensive when looking at other ICF systems.

The house builders bible does a good chapter on this. When you build, you're paying for walls to enclose a space, more wall more cost. A 10m square encloses 100m2 of area for 40m of wall. A 20x5 rectangle encloses the same area for 50m of wall. The wall/space ratio gets worse when you have L shaped buildings etc. Following the same logic, two stories is more efficient than one. Gable end walls allow rooms in roof etc. Expanses of glass look nice on plan but are expensive, drive up the cost of the rest of the fabric (has to compensate for the less efficient insulation) and can lead to overheating in summer. Good design can give you equivalent light and views but for less glass - e.g. we have some very neat vertical & horizontal slot windows.

I bought mine from a local van park (was too tired for them to rent out anymore) £1700 plus £500 delivery to site and positioning in back garden from their local mover. Was a two bed, two bath 40ft x 12ft. Moved in Easter 2015 with wife, two junior school kids and cat. Moved out Aug 2016 to new build. Was a bit nippy during winter (even with the gas fire) until we got a tip from a friend to run a dehumidifier round the clock which removed residual moisture and pumped out a bit of heat. Perfectly comfortable after that. The prob with gas fires is that they emit lots of water vapour which then condensed out at night and makes the floor a bit damp and therefore cool in mornings. Bigger issue was summer heat, no easy way to get rid of that apart from keeping blinds down until east sun has passed overhead in mornings. Tried to sell it on to other local self builders with no luck. Sold it back to caravan mover for £1000 and he took it to a fruit farmer somewhere. Net cost of accommodation for 18 months was £1200, or £122/month. Electricity bill was a bit higher than usual due to de-humidifier but we would have been spending £2000+/month for a local 2/3 bed rental - so an additional £35000 to spend on the build. Also huge advantage to being on site during build from a security pov, see whats going on and also being there when trades need to check something or a delivery arrives. Did we enjoy it? Not particularly. Was it unbearably awful? Not particularly. Was it worth it? Absolutely.

Sorry, we can be very quick to jump in with questions and answers and sometimes forget to say hello!

Forgot my manners to welcome you to the forum

We used shuttered concrete and SIKA waterproofing (no membranes inside or out), also warrantied. This is the key bit, irrespective of the system, if there's an insurance backed warranty then you can sleep easy.

We used two SEs, one was part of the timber frame package so we did not interact with him directly. Second was commissioned by us and used the spec of the TF above (point loading etc) and the output of the GI to design the basement. It was a full structural design with steel schedules etc that we were able to take to contractors for quotes. The practice I used also specialise in ICF, believe they are now called Build Collective in Bristol.

As mentioned endlessly, MVHR is not very effective at raising or lowering room air temperature as the flows are very low and air is poor at moving heat. It's there to supply you with fresh air that is warmed to near the same temp as the extracted air by recovering the heat. Can act as a trim in a very efficient house. My view is that your house is ICF then it's probably very airtight and well insulated, therefore heating in bedrooms is probably not that necessary - sufficient heat should convect from downstairs, plus solar gain and heat from occupants and powered devices to make the rooms comfortable, especially if you like them cool (as I do). Did you model the house heating requirement before specifying the system? Is there a way to isolate the upstairs UFH circuits and see how that goes? Our passive timber frame only has UFH on ground floor (timber floor) and it's off apart from the winter months. GF air temp stat set to 20, bedrooms comfortable.

Our 120m2 slab was in basement so never considered floating it but I remember our fifth and last concrete load arrived hours after the previous four - the pump needs to keep running (and they are noisy) so we didn't wrap up until 6.30pm.

I recall from others here that power floating can be a bit stressful as it can only commence when the floor is starting to go off and if the concrete is late to site you can be doing this late in the evening much to the annoyance of neighbours etc. Once set, concrete floors are also susceptible to staining from oils and other liquids, until sealed they are very absorbent. Then you have damage from drops, drags scuffs etc. Corex is better than nothing but not very durable, you'd need to use ply or carpet to really protect it and that won't be cheap. In a similar vein, we only installed our final staircase once the complete build was finished and all trades had left. We used cheap MDF stairs during the build and when the final stairs were ordered, we had all the final finished floor levels to measure from. You can get a microscreed (2-3mm) that gives a polished concrete effect, we looked into this but went with resin instead.

Agree - accept that things will go wrong and focus on prevention and solution but not blame. Many trades have their 'way' of doing things and unless explicitly instructed to do otherwise, will default to the usual. If you expect different then make sure they are aware of this and that it's detailed and costed. I remember finding half of the Velux insulation kit in the skip as the roofer 'didn't bother with it' but then again I assumed that what was in the box would be installed and we never explicitly discussed it. You learn as you go.

I had the same feeling - early on, after we had PP but before we'd landed on a build method, I commissioned a potential PM to do a PHPP analysis and develop a cost plan. The proposed budget (very thoroughly calculated and itemised by a QS) was about 30% over what we had anticipated and his fee was a % on top. However he said that his fee would 'pay for itself' by bringing the build in under this budget. We did PM ourselves, eased by having a comprehensive TF package, and came in 20% under his original figure, even after adding some additional items.

Depending on the build approach, you can PM without doing nuts and bolts counting by splitting the works in to packages and getting trades to do each bit - essentially you're taking the role of main contractor. For us, this worked well as the two critical stages - demo of existing and construction of basement, followed by erection of a timber frame package, were substantial and discrete elements. We then worked directly with window supplier, roofer, render, electrician, plumber, joiner, plasterer, tiler, kitchen, decorators, flooring, landscapers etc. contracting with each individually. Most contractors were supply & fit (so zero rated for VAT) but we did source all the plumbing second fix items, some lighting, tiles, flooring etc I found being honest and upfront about what we wanted and what stuff cost and what our budget was is key. You need to develop a relationship with each trade - be nice, offer tea & biscuits but try and avoid over supervision (let them get on with it) but don't be a push over also and be prepared to ask questions.

For weeks on end yes. For a few hours when there's a fire nearby, probably not. We have no opening windows in the bathrooms so do run it year round - summer bypass when its hot.

Agree, a few hours while it's particularly smokey outside will not make any difference.

I was of the same mind but when you have trades on site, first fix, plastering and second fix plus some flooring etc in that space were not massive additions to the budget. Always worth getting the quotes with and without basement for each stage and see where you get. Given you have insulation on the outside wall, you can always do the industrial look and get surface mount electrics on bare concrete walls

I did wonder if it was Kore given the detailing. Are you putting any UFH in the basement slab? We decided against and haven't regretted it as that part of the house is always at a comfortable 20o year round.

I just put in 'framing timber' and 'ironmongery' for all the bits & bobs we used to build the hall cupboards. No issues.

Exactly what we did. 3m of pax in a row in each bedroom and the joiner framed them in MDF pained same colour as wall and they look built in. He said he could not have done it any cheaper in MDF, even allowing for VAT. Ikea have some nice lacquered finish doors now as well as the plain white. We've also added a few mirrored doors to the kids room and our dressing room for full height effect.

We had a similarish challenge - long drop wire from pole across road to our previous house that we needed to demolish. We got OR (via BT) to initially move the wire to a container at the site perimeter and when the house was complete we got a quote to take it underground to the site perimeter vs another drop wire - we obv. put in all the ducting on our side. OR survey guy said he'd produce a quote but recommended doing our own street crossing and pulling our own cable through and leaving it at the base of the pole. When they came to do the connection, they just made the join either end as part of their standard fee. Saved about £3k doing that. SO - you may be able to negotiate similar - if you trench and run suitable duct (grey BT spec) from pole to pole and then pull suitable cable through, you should be able to negotiate down the fee. OR may insist on using their own cable but its the trenching that will really cost you money as they use a 3rd party for this and they charge by the metre. You can also ensure the trenching follows a route that suits your build. +1 for avoiding wire 'accidents' - it's a risky enough strategy when you're the only person at the other end but if you disconnect 5 neighbours then you'll be in very hot water.

Pretty identical to ours. Few notes... I'd see if you can get away with EPS200 or 250 under the slab, just see what the loading is from the SE and then get them to check this table https://www.specifiedby.com/styrene-packaging-insulation-ltd/stylite-eps-geofill-void-formers/geofill-compressive-strength-factsheet_4eeaa0ea.pdf We were able to get away with EPS200 which saved more than a few quid and were easier to move around - I used 2400 x 1200 x 300mm blocks which were about 30kg each. Didn't attempt to cut them but just laid them flat on the blinding. As we were using traditional shuttering, I didn't need to use the EPS to do that and I let the EPS extend the slab by about half a metre all round. They did not need securing, once flat and butted up to each other they were going nowhere. I laid the radon membrane over the slab EPS and the crew just built up the steel frame and shuttering on that, had a 150mm kicker to start the walls. We used GRP light wells (MEA Bausysteme) which come with a 200mm XPS insulated collar which tied in nicely with the EPS - I put those on first. The crew had formed rectangular window holes to the dimension of the light well so the XPS went neatly round these. Was fun keeping it in place until the special adhesive went off - lots of horizontal and vertical props. I glued on the vertical 200mm sheets of EPS70 with LE foam (must have used about ten cans and a gun) - spray the concrete with water first to get a good adherence. I then covered the EPS with 2mm core to give it a bit of protection during backfill. Just used spare nails on site (there were 100s) to pin it in place. 200mm EPS was cut with handsaws and an electric chainsaw - makes a lot of mess so do it inside the basement box and create your own giant snow globe Now our land drain was at the base of the slab to a soakaway - is your groundwater level too high to do that? Meant that and percolated rain water had a route away from the slab base. I'm not sure why you'd have one so high up tbh as the water will run past it and down through the stone. Backfill was pea shingle to landdrain then stone. When we got to light well level, we laid a bed of pea shingle and secured the lightwells to their collar (bolts and supplied sealant) and filled around them.

The contractor did it - basically they unrolled about 15m of it (it's 4m wide) and weighed it down with a few rocks and flapped it away from the rock infill side. They put a layer of rock down and then flapped it the other way and put a layer of subsoil, repeat until you reach the top.