MortarThePoint

Thought I'd add a picture of the chassis. It's pretty high for a shepherd's hut, but use what you've got. Lots of sanding and red oxide paint in the coming days.

I'll work out where to put the windows more from the shepherds hut perspective. It may be a while until it gets used as a site hut unfortunately

Covid-19 has stopped my self build in its tracks just prior to dig and pour of foundations. I have massively got the twitch to make something and have some materials on hand and time to do it. Thinking what to make I have decided to make a hybrid site hut come shepherd's hut. I have a couple of old (but sound) 5.2m x 2m trailer chassis which I'll use one of for this. I stripped the 100mm coldstore panels off a building that got demolished and have 100mm Celotex that came out of the slab. I've done some basic CAD and thought I'd share what I am up to and see if anyone has any thoughts. Haven't thought about windows or internal stuff, also likely either clad with feather edge or plywood and vertical battens (US style). Base is 5.2m long and 2.2m wide so overhangs the side of the trailer by 100mm on each side. Doorway is currently 1800mm wide. Shown as 2000mm high but the panels could be cut to raise the ceiling a fair bit. Front View: End View: I haven't spent the time filling in the part of the panels that would extend up to to meet the curved roof. Section View: I've allowed for the roof / ceiling to be made out of curved corrugated sheet steel with 150mm of loft insulation and 5mm sheet plywood curved to make the ceiling. You can see the uncovered frame of the endwall. Notice the timber cross braces that extend into the 'living space' but rigidity. Skeleton: All made of 4x2 (95x47) timber. The insulated panels are quite strong themselves but need to be restrained. The plan it to use scrws top and bottom into the timber to secure the insulated panels. End wall: All timber 4x2. Propose to use 18mm plywood screwed to interior surface to provide shear stiffening. Base: All 4x2 timber with 18mm Exterior grade plywood sheets screwed on top or bottom (if bottom then add timber flooring to inside of hut. I think it needs: Skeleton: 53m of 4x2 untreated + 4 sheets 18mm plywood Base: 57m of 4x2 treated + 5 sheets exterior 18mm plywood Roof: 13m2 curved corrugated steel, 13m2 150mm loft roll, 5 sheets 5mm plywood When finished as a site office I can line the insulated panels with 5mm plywood and paint etc adding guestroom like furniture. What do people think? Will it stand up?

Well that was a close call! I had a feeling that this evening's announcement was going to be what it was and that has stopped work. Thankfully the dig and pour was due to be tomorrow and not today, otherwise they said they would have had to dig out the pour and start again (at their cost but still). I'll be doing a trickle of small jobs on site, but that's it for now. No materials and no foundations in so not much I can do. I'd been measuring their mark out and it was spot on, so I was getting excited about the foundations going in. Could be a few months now, but at least it's not half way through. Weird emotions relief and disappointment at the same time.

I'm sure there would be, not quite sure what but I have a vision in my head of the mesh hanging from timbers laid across the trench.

No keen to have a polystyrene separator, feels like an expansion joint. Probably made sense for your setup but I'd like the foundations to behave as one.

Hi I'm probably being a bit vague here. The clay is stiff/firm but above it there is sloppy wet cay that is I guess the water table. So I guess that means we are below the water table.

The subsoil is very sloppy and he foundation quite long with a number of corners. They are suggesting doing the blue shaded bit on the first day and the orange shade bit on the second day:

Due to the nature of the soil the ground work team don't think they can dig the whole foundation and pour in a day so they are proposing to pour in stages anyway. They should be able to confirm that cement is deliverable first thing and then dig and pour same day. Any shutdown that might be announced is unlikely affect the day of announcement so at least that day's work can be concluded. There is the risk that the second day gets called off which wouldn't be good as the concrete is more likely to 'bond' the two halves together if it is fresher I imagine. Does anyone know about any downsides of having the foundations done in two pours like this? The Structural Engineer has recommended "to dowel foundations at the construction joints, use 6no. H16 dowels, 600mm long encased 300mm deep in concrete on each side of joint; install dowels in three rows evenly spaced and providing minimum 150mm edge distance." I don't know how many would be on each row and will ask. The ground works team were talking about starter bars. What do people think?

The Structural Engineer has specified a maximum of 750mm of blockwork below external ground level and maximum 450mm below internal ground level (i.e. under void). Looking at these two pictures highlights that I should make sure it all works as the Structural Engineer has finished floor level way above external ground level whereas it will be 150mm above external ground level. The floor beams and screed are 375+75=450mm thick and the void 300mm so that makes internal ground level 450+300-150=600mm below external finished ground level. Based on this I'd expect the pour would come up to level with the ground under the void. Ground level outside has been reduced during demolition and needs to be built back up by 600mm.

Good thought about the insurance, they may have specific conditions. I'd take precautions anyway.

It doesn't drain well and I think the bottom of the trenches will be within the water table so it will be flooded one way or the other

That's comforting to hear. I'm just not really aware of what could go wrong as people normally don't have a delay at this point.

They are very open to discussion so I we will be talking things through. I expect from their side they will want to carry on and may not be able to weigh up the risks dispassionately as it's their livelihood. I need to find out how long it will take them to dig the trenches, but they are not going to be able to do the full dig and pour on the same day so there is a real risk that the government announces some form of shutdown that affects concrete deliveries an leaves us with an unstable hole to fill.

Good question. It's a fixed price job but they are a small independent company and this sort of situation hasn't arisen before so it's anyone's guess really. I have to assume that it would be my risk in the end.

I'd like to acknowledge that there are people with bigger issues, but hoped I could ask people's advice. The groundworkers are onsite as planned and progressing with prelims prior to digging foundations. I am worried that they may get in to the dig and it turns out that, due to Coronavirus restrictions, either they have to stop or their supply base stops. It strikes me as a disaster if the trenches are dug (1.5m to 1.75m depth with claymaster) and then can't be filled for a number of months. I'd really appreciate your thoughts. Should I call a halt to things now as the situation is changing rapidly and one day everything may be possible and the next nothing possible.

+1 for ProDave's response There are lots of factors to consider including nearby trees, future planting requirements, volume change potential of bearing strata and so on. Clay can be complicated by the fact that it can swell (heave) or contract (subside) depending on water levels and how thirsty nearby trees are (or were if cut down). I'm not trying to scare you, but I personally left that side of things to the pros with their experience and insurance.

Sounds sensible bissoejosh. Did you have to have verification testing done afterwards etc. I'm planning to use a specialist installer for the membrane work as then any issues with subsequent testing will be on their head rather than mine. I'd like to be an informed customer though rather than going at it without a clue, hence the thread.

It may be unusual, but we have designed a precast concrete product in for our ground floor. A bit more expensive than beam & block, but It has the following key benefits: has insulation already attached to its underside can be installed by manufacturer in a day and then ready for next stages puts the concrete of the floor inside the insulated envelope increasing the insulated thermal mass Due to some Made Ground on site and not wanting the vagaries of Ground Gas well testing, we decided to incorporate a gas membrane into the design which replaces the DPM. This gas membrane will be installed above the concrete floor and then ultimately have screed over the top. There is the option to do perimeter first and then infill, but cheaper to do all as one. What I am wondering is how I leave all this for the subsequent year or so as the rest of building works goes on. Options that spring to mind are: Just do perimeter and leave concrete slabs exposed (probably grouted), infill later Do full gas membrane and cover with full depth of screed (minimum 75mm) including underfloor heating pipes Do full gas membrane and partial cover with screed (? e.g. 30mm ?) to protect the gas membrane I expect people who have used Beam & Block and a gas membrane have faced the same quandary, so it would be great to get some pointers.

All sounds like fair game for studding on the log burner. I'll look out for screws and nails. There's a 20t machine here with selector grab which has loaded one wood skip with wood from an old barn I wouldn't want to burn already. I'm paying a flat rate for the 40yd bin and suspect I over estimated the weight it will be when full.

If I were you I would ask by email rather than over the phone. The emailed response is handy to file away.

Would you have any reservations (treatment?) on an open fireplace as a friend has one and I could offer him some?

It's what I figured. May take me a while to separate it from the OSB etc, but should keep me warm.

I have already made a 'shed' out of ply and studding ? Overflow can go raised off the ground under a tarp.

I've told the guys doing the demolition that I'd like to keep the timber from a barn which consists of studding, plywood and cladding. Plywood is always useful and they are soft stripping that so easy decision. The cladding is a bore and will get burnt (modern so I presume no nasty treatments). I think there may be OSB between the cladding and studding which will get trashed by the Selector grab and so useless. I was thinking I could keep the studding to burn on the log burner. Is this a folly, or can someone say they've burnt such on their log burner and it's a good idea? I'm wondering about a 40 yd RoRo for wood to take the studding, OSB and cladding as it could save a lot of hassle and keep the place tidier. It's difficult to know how much the skip will pack and so what weight to expect in a 40yd bin. Any thoughts?