Spinny

PS Are the joists 'at the top' on your sketch done the same way with a span of 9.6m ? I guess the 2.9 wide section top-right could perhaps be joisted at right angles, instead of all joists being 9.6m long. Also maybe consider what apertures/fixings will be going into the ceiling and consider whether the joist positions will be compatible with these e.g. loft hatch/ladder, downlights etc. (My carpenter was good enough to adjust a couple of joists above a kitchen to make room for specific feature downlights). It is only something you learn too late - that the structural drawing should be overlayed with the lighting plan and the room layout to resolve any clashes.

When you have fitted the first joist in situ and confirmed that it is the correct length and fits well, one possibility might be: - move that joist across the area as a tester to help establish whether the walls are square i.e. all joists can be made to the same length - take it apart and remove it. Then take it outside and use it as a template to cut and drill the remaining lengths of wood to make up the other joists to the same length (if it is square) (However I am not sure whether it is best to have all joists with identical overlaps and identical bolt positions. It might be arguable that different length/position of overlaps and bolts on different joists would give a more robust structure less likely to fail in the same place across all joists. But I guess your SE would say it is designed so that any one joist will never fail anyway.) PS I am not a carpenter and probably don't know what I am talking about.

Our extension slab was about 7.6m by 5.5m and about 120mm thick with a single layer of reinforcing mesh held on concrete mesh men at about 50mmm up. So only half the size of yours and we had no expansion joint. Specified by our structural engineer. It has been down 2.5 years, still not floored over, with the heating pipes operational for 1.5 years. Looks fine with no cracks. Plumber clipped the pipes to the mesh with zip ties. I went around after he had gone cutting off all the zip tie ends he left sticking up.

We had the suppliers come and measure up the openings for our doors and windows. They tend to allow 4-6mm tolerance all around the perimeter - doubtless reduces their risk. Beware the laser level. One supplier measured at survey, then measured at fitting and declared our floor level to be 12mm higher than it should be. Wouldn't accept it when I explained that was impossible as the only change was they measured from top of joist the first time, and from top of floor boarding the second, and that was fully allowed for. I bought an old world water level - ultimately showed their measurements were wrong - used over a 9m distance, and comes in handy for finding levels between the inside and outside of a building.

Intention is to seed the new lawn rather than turf it. I did this once before about 30 years ago with good results using some good seed. We have a clay soil type, which does show some cracking in very dry conditions but seems quite fertile. There is a big variation in top soil pricing (£50 to £150 per 500L), but I also suspect there is a big variation in 'quality' too. We have the additional difficulty that access to the back garden which needs to be levelled is via a side passage only 800mm wide, and the side passage wall is just now being newly k-rendered and cedral cladded, so we need to avoid damaging this. (The thought of some landscaper's teen labour crashing into stuff with wheelbarrows doesn't bear thinking about). We are also in a suburban road and a lorry load would have to be tipped on the public road and/or else block any use of our driveway. I have bought a few 25L sealed bags of topsoil on offer from Wickes and these are easy to hand carry down the side passage. 20 off 500l bulk bags equivalent would need 400 bags though. Any views on whether this is good stuff or crap ? Honestly not sure how to assess the quality of new topsoil, and if you don't like it after it is delivered you are going to be screwed ?

Do you know how level the concrete will be ? Our builders said the slab for our extension would be level to within 6mm, but only had a man hand tamping and floating it. It was only level to within 24mm and the level was 11mm higher than it was supposed to be. We had to change the floor make up in the connecting part of the main house, and the flooring contractor will be using levelling compound across the top of the slab to correct the 24mm variation. You probably have some very good pro's doing yours, but you will still want to check the actual level variation once it is poured and floated, just in case any parts need levelling compound, or different door apertures vary somewhat in level. Just a thought.

I have about 200 sqm of our garden to level out for a new lawn. I will need to get some top soil in but am a bit annoyed as we had a landscaper do a bit of work last year and they insisted the old lawn should be scraped off, when I could have just killed it with weedkiller. The result seems to be that they effectively skipped a couple of inches of the existing topsoil with the lawn - effectively costing me £1000's just to replace what they skipped. Doesn't seem right to me. Anyway I am wondering how level is a level garden lawn - we want to achieve something that looks flat and contemporary. Should I be aiming for completely flat, or should it have a slight drainage slope, and will it be noticeable if I put a small slope on it to save on topsoil. It is about 23m long and 8.5m wide. So even a 5mm per metre or 1 in 200 slope would save me 4 inches of topsoil at the far end and about 20 bulk bags of topsoil it seems.

Still waiting on a quote for an oak strip wood soffit for an overhang. Still in two minds about the problem of oak and timber ageing to a grey colour from UV light after a year or two. Therefore also wanting to look at manmade wood effect alternatives that will not change colour and be low maintenance. Any suggestions/suppliers ? Has anyone on here done something similar ? (Slightly wonder if LVT click style planks could be used ?)

Renderer is here and has kindly routed out the blockwork, put the cable through some channel I had bought and mucked it into the wall to make ready for rendering over. (just thought I'd say what happened rather than leave open ended)

Who owns the shared access way, and precisely what gives shared access rights over it ? Are you measuring from the outside of the house wall, or the outside edge of the eaves and gutter ?

Personally I'd say have some consideration for your neighbour. Even if you can do something it doesn't mean you should do it. Probably not a popular sentiment these days.

Should I use this stuff ? https://www.insulationuk.co.uk/products/tekwarm-reveal-board-high-performance-laminate?variant=43387649261749&utm_medium=cpc&utm_source=google&utm_campaign=*Pmax|Ins.Plasterboard30+&gad_source=1&gbraid=0AAAAAoNNCLQ_tq0b6Prkw491vqllba1g2&gclid=EAIaIQobChMI7_mygKjujAMVrpFQBh2LXgvDEAQYASABEgJc7_D_BwE

You don't need a concrete floor for u/floor heating of course. That photo I posted above now has underfloor heating. We were going to have a between the joist system but changed to a within the board system from Omnie when the builder cocked up the level of the concrete slab. (Insulation between the joists, 22mm pre routed board with a matching pre routed overboard - about 35mm thick on the joists.)

See the sketch. I have the end of an external wall running into the internal area alongside a window. I am wondering what level of insulation to use across the end of the spur of external wall (where the external wall was cut back to create an opening). I can use some insulated plasterboard on the inside of the window reveal, but the end of the spur will be plastered over (wet plaster) with the adjacent brick wall. I guess I need a little bit of insulation between it and the plastering to avoid a possible cold spot in a utility room. Suggestions ? Thin piece of PIR ? Something I could spray it with ? Aerogel matting ?

Photo from when ours were done in case it helps. Took them 4 goes and a visit from the structural engineer.

With a Talentofill. In our case fed from our shower mixer, so no taps needed at the edge of the bath anywhere. Saves 3 or 4 inches when fitting stuff into 2m by 2m and looks nice and contemporary. If you think about a bath the dimension you care about is the size of the inside 'hole'.

Wasn't sure if the render would attack the cable insulation over time ? If clipping to the wall, what clips, plastic ones or the metal wrap around ones ? Does any metal have to be stainless steel to prevent rust (including clip nails) ?

@ETC Thanks. You have got me wondering, do you think I should be adding some insulation on the inside as sketched in red in the attached image ?

Should they not have capping - plastic, metal ? and then render over that ? And presumably fix the outside socket box onto the render afterwards rather than render around it ?

Our bathroom is 2m by 2m. We put a narrower 725mm wide door in to the same pattern as the other doors - you would never notice. And don't forget you don't need to have bath taps, we don't.

Couldn't you cut a section of the joist out and put a couple of trimmers in hung off the concrete block wall to create a gap for the toilet pipe wherever you need it ? (Or can you not do this with posi joists ?) Not keen on close coupled myself, much prefer the look of back to wall with a hidden cistern. Looking at your layout again, I am not sure it is ideal to have the toilet opposite the basin. The photographed layout above looks better. I tend to prefer the toilet somewhat tucked away as it is not normally a focal point and is a possible source of hygiene risk. Build a half height stud wall out across the end of the shower nearest the window, then turn the toilet through 90 degrees and back it onto this stud wall, conceal the cistern in the stud wall. Then have glass panel from above the stud wall up to the ceiling. ? (Would allow the toilet roll holder to be mounted on the wall then). Then you could push the basin down towards the bath more. (Even connect it to the bath with some cabinetry creating more storage and a longer counter top with a large mirror or mirror and shelves above for ornaments/pot plant ?)

Agree, storage is a big thing in our bathroom. Surprising how much stuff a family wants to store out of sight from spare loo rolls, spare soap, his razors, her razors, tons of goops, cotton buds, cleaning materials, scissors, weighing scales, air freshener....lots of spares because who wants to run out of bathroom stuff.

People may be nicely silhouetted against the window when getting in and out of the bath at night ? Where will you put the extractor and the heated mirror ?

Now the daylight is stronger and longer, does anyone know what the position is with pipes and plastics left outside and UV degradation ? I currently have the following uncovered: MDPE ends coiled outside where they come up out of the ground. Some spare end of coil MDPE barrier pipe lying about Multiple lengths of 110 underground drainage pipe lying outside. Some black and other plastic type sheeting Some black pipe fittings/silt trap Some black sheathed network cable exposed Some lengths of black covered armoured cable exposed (I long ago covered over all tail ends of plastic membrane like radon membrane etc that stick out, until they get cut off at the right length.)