Carrerahill

Hi Ferdinand, I am reading your thoughts with interest, I am sponging up all the information at the moment and the conclusion I have come to is that there is no hard and fast rule, and for every "rule" I read, there is a contradictory one! The solemn area is well ventilated and I designed it to work well, even opening up a crawl space into the existing house which also helps to ventilate the whole house and the new extension. I nearly filled the lot in and concreted over it but went for a suspended timber floor for various reasons but also because I wanted access to the underside, particularly the kitchen area as I just see burying everything in concrete as a pest. My general concern is driven out of building something set to fail from day one, that is not me, my principle is that things get done properly and I just want to ensure the best for my property. The interesting thing is that the previous owner used EPS throughout the entire ground floor between the joists and also the entire loft space - I am not noticing lots of damp or mould, it is a 60's house, very traditional with lots of breathing going on. The house is high on a hill so we are well drained too which helps. So am I worrying about something very theoretical? Do I just use the PIR I have sitting there and keep it high so the OSB is hard against it, this then exposes a decent portion of the joist for ventilation. But what happens if there is moisture trapped above this PIR - does it eventually get driven out with the heat from the UFH. It would need to come through 11/18mm OSB, 25mm biscuit screed, 5-6mm floor leveller, Amtico or Karndean on a HT adhesive... seems that moisture won't really have an easy route out. Something like this: As seen HERE: https://www.ecologicalbuildingsystems.com/post/ask-expert-thermally-upgrading-suspended-floors The idea behind the breathable membrane, a bit like a roof, is that it creates a wind break, several articles I have read over the past 24 hours suggest that with the open fibre of a glasswool, rockwool, hemp, wool, whatever it be, has a reduced efficiency when exposed to a draught, so the breather membrane allows vapour to escape but cuts down on the gale blasting past. I have been speaking to Knauf this morning and their technical guy said not to fit the VCL above the floor as that would create an issue - that does make sense, but then again, are this lot then talking nonsense? Does anyone really know? Solution: Cheap renewable energy and build buildings like we used to with big draughty cavities and lots of air bricks!

That is the conclusion I have come to. I am totally rethinking the insulation now. I am thinking, breathable membrane (left over from roof) to the underside of the joists, some Knauf roll 44 in-between the joists, then a VCL over the joists, then my OSB. This will give me a breathable joist with insulation and a barrier to stop warm moist air heading down through the floor. I now have all this 100mm PIR - I was going to use it in the loft of the house, but I then kept realising I was going to form the same issue with condensation - the only room I can lose about 2 sheets into will be the bathroom as I will be pulling the ceiling in so I can VCL it before I refit then 100mm PIR can go in above.

I would lay the drains first - only logical way. You can lay the drains and use some weak mortar mix to give support at various points if needed.

Almost all fixings in construction should be of corrosion resistant type unless it is at a point in the building where really water or dampness will be guaranteed non-existent - good luck proving that! This is an issue with a lot of timber construction where they used cheap thin nails, they rot then the frame effectively becomes weak as the thing isn't fixed anymore!

The extension now has floor joists - finally! The insulation is to be 100mm PIR between the joists - fine I have towers of the stuff sitting there at the ready. However, I also have sheets of 50mm celotex, unfortunately they have already been cut to 325ish-mm x 1220mm. After I finished 95% of the joists last night, while soaked to the skin (coming too and from garage with the blocking for the floor during torrential rain), I had the brilliant idea that I could fix the 50mm celotex to the underside of the joists as an extra, taping the joints to create a big vapour barrier/insulation layer. This also gave me a home for this Celotex. So I dug out some 75mm screws and penny washers and then decided that as I was soaked, lying on the concrete to screw this in would probably not be a good idea. I came inside, got cleaned and opened a bottle of red wine instead. About 5 minutes into my first glass of red I suddenly realised my plan was flawed. In effect the joists would become sort of sealed in and ventilation would be, well erradicated. So I am trying to work out if I am worrying too much, or if I have a valid concern here. The floor is timber joists, with OSB on top, UFH pipes on top of the OSB, battened out above joists to clear the pipes with biscuit screed in-between and then some levelling compound over the lot then Karndean or Amtico. Thoughts, I could knock the 100mm PIR down the joist so it was sitting hard against the 50mm underside PIR, that would then form a 75mm gap above it, which could be left vented to the inside of the walls which may allow for a little ventilation, with the UFH pipes above it warming the OSB some heat would go down, the heat might start a convection cycle and convect heat up the wall (on the inside of the PIR cocoon) thus keeping it ventilated and dry? Or do I under-fix the 50mm PIR, then put in some battens to guarantee a gap, then bang the 100mm PIR down onto these battens so it sits flush with the top of the joists, then try and ensure ventilation through the joists? Do I just not bloody bother? I could always just put the cut pieces in on top of the 100mm PIR and foam the gap either side - I am then left with 150mm PIR effectively. I would have just done this but the sheets are too narrow for my joists centres (400mm centres), as said above, the Celotex is 325mm-ish wide so they are a little small.

This is what I expected too. I am sure I will find out soon! I am going to have an excavator here in about 4-5 weeks so it makes sense to trench for the new water pipe, I will lay it myself. I have got a Scottish Water inspector coming round later this week to discuss the route as it will not follow the exiting route due to mature vegetation and hard landscaping I don't want disturbed. He can advise exactly how he wants it all done - I have been advised that he would also come back to inspect the work, so as long as I follow his guidance to the letter I should be grand. Only down side is apparently it can take 20 days for them to come and make the connection, so I need to work out a way of having the end of the pipe ready to go into the pavement while maintaining the use of the drive. Watch this space folks - any anyone who has experience of this please let me know how it all came together etc.

Has anyone had any experience with Scottish Water - or any utility really, on connecting a new water pipe where a lead pipe has been replaced. Does anyone know roughly what this costs? I have been led to believe as it is replacement of a now banned pipe material that they will make the connection FOC. Thanks

I don't have an iPlayer account and at present don't care to have one. What is the gist of it?

Well the cavity is probably open behind this part, the surface is then cold, so it's a perfect spot for damp and quite common.

Damp. To solve first see if you have a water ingress issue or condensation. It is going to need to be fixed so I would probably hack the plaster off to the brick or if PB I would remove that and the story will probably go on. If this sounds like a bad plan and too much work then try and solve the damp issue through assumption - then once dry as a bone re-skim with thistle jointing compound as that will go on smoothly even for a novice plasterer. I would do a little more digging then come back here with a report and the solution will be forthcoming.

I hear you! I am in the dumps just now with my build. Ready to sell all my tools and give up at the moment and I don't even have any reason too really, just all going too slowly for my liking and feel like time is conspiring against me to disappear while nothing of note has been achieved in a month. A summer month at that! Just had a roughcaster here - he has left me disheartened as I suspect I am no further forward to finding one! He seemed to offer more thoughts on everything but his bloody part of the job and kept telling me what I would need to do to certain parts of my build. The gutters are not on fully, "Oh are you going to fit gutters, you will need gutters or you will get damp problems", what is going on there, pointing to part of a roof that hasn't been tiled yet! I bit my tongue and managed to hold of telling him I know more about buildings than he does! Unless his price is particularly good I don't want to see him again - even then, I don't think his price would be worth it!

It depends. You can get 240V cherry pickers which plug in - if you look at the motors on the hydraulic pump(s) it may be possible to get direct replacements that are 240V - control circuitry could be left as is and just run it using a 12/24V DC supply (assuming that is what it has) and a relay to run the motor on mains. It is probably how I would do it - simply put back in the DC motor if you want to change it back. Alternatively as @JSHarris says, it will probably demand a fairly high current and therefore need a hefty transformer but not impossible. What about connect it to a permanent charge system? I am not sure if yours is 12/24V but you could fit a constant supply charger to the cherry picker and a mains lead, when in use simply plug it in, the thing will charge all the time and when you use it the load will come from the battery - presumably you are not driving about in it constantly and going up and down in which case the constant charging will effectively leave you with a "mains" supply. Lot's of options. It's just how far you want to go.

Grey Water into soil - yes - I do this too. I think a shower or bath down a soil pipe is a good idea. dBlue is good stuff, a little pricey but you don't need much, it removes the splat splash tinkle noise from your wall.

The two which combine externally at the IC, one for upstairs, one for the downstairs WC. I would personally not want to have the first floor soil share a stack with the ground floor WC - blockage could result in a nice poo fountain. It is not going to take much to have them separate. Utility and bed 4 en-suite also combine, albeit internally. I guess you could tie the ground floor WC into the stack in the wall by coming out the toilet and going 90° into that stack. But it wouldn't be me. I have actually just done some new waste and soil pipe for my extension and I have got the kitchen on it's own waste and not tied it into the soil pipe which runs right down through the wall about 2m from the new sink location. I always split them. I wonder if optimal is the correct term - I get the impression you may be trying to value engineer it - which often results in less robust design. I wouldn't want the stack going through my dining room/living room wall - you will hear it - I would either use Marley dBlue or move it.

Just past and present really. Late deliveries, increasing "delivery charges" - inadequate delivery time-scales, prices which go up in the cold weather, one friend only had one supplier serve his area and the prices became so ridiculous he switched to wood and has never looked back.

It costs an absolute fortune. If you need tanked fuel go for oil. Issue with gas is you are at the mercy of usually 1 or 2 suppliers and the monopoly they run. I know loads of people who really really hate their off-grid gas supply and the headaches it causes.

You seem to know a bit about this stuff - I have an incoming MDPE pipe under my current kitchen - I recall from the last time I was under the floor that it changes to a 22mm copper to go up through the floor, then stop cock. My kitchen is moving to the extension so my plan is to connect a new piece of MDPE to to the original MDPE and run it under the floor to the new kitchen and then redo the stop cock and reconnect the rest of the house which will make for a neat install and no stop cock in a soon to be office/den. So does that sound reasonable? Also - I need to run a pipe out to the garage, should I come up on main stop-cock, then Tee back out of that, another stop cock and then MDPE back out and under the floor to the duct over to garage. Or could I Tee off from the original MDPE - 1 to kitchen for house supply and 1 to garage. I could always run that pipe along under the floor and have a stop cock to garage under the floor in the hall cupboard, so if I wanted to isolate garage I could lift a hinged trap and turn it off, or do I just run a supply to the garage and have a stopcock where it enters. The only downside to this is the only way to isolate the supply from house to garage would be from pavement - however, that is the case with the house pre-stop-cock anyway so does it matter...

I think there has been a bit of a glut over the last year or so as there has been a huge amount of infrastructure work done. Local authorities went a bit mad after the bad winter and started resurfacing roads like there were no tomorrow.

£60 a wagon round here - that would be a 32tonner - £1.88 a ton! £40 for the fines from the road-sweeper which dosed with used engine oil or diesel makes a brilliant running surface!

Possibly in some, to be honest the minority of situations, but I can assure you road planings are still very much available. Where resurfacing works are being done, the planer strips them into a 8 wheel tipper and they get taken for "recycling". Recycling can mean anything from using them as fill elsewhere to using them to make new tarmac products... the fact is the recycling strategy involves plenty of them being sold. Arguably road planings have always been recycled as they never went to landfill and were always used for something - even if dumped temporarily in a vacant site etc. until they were used. Where a road is being resurfaced they want the old stuff out and the new stuff turns up to be laid, they are not going to re-batch it on site unless the project is frankly on a massive scale. On bigger civil projects it will be used locally if it can but the majority of the time it is taken away.

2.5tons? That doesn't sound enough at all. Hardcore is £12-25 a ton depends where and how much you buy it so if it was 2.5tons it would be £30-75. Find some road resurfacing works and buy a truck load of road planings. £60 a load seems to be the going rate.

Just been through this with Kingspan and Quinntherm with the same roof make up. 50mm ventilation is a must - which is why I now have insulation under the rafters too as I could not fit it all in-between them - mind you, it's better as it removes cold bridging!

Foam - depends where the duct comes from and goes and if stuff got into can it end up in your house etc.

You are not having much luck! I'd come and help you for the weekend if I was closer (but I would want you to come and help me the following weekend) 2 people achieve more like the work of 3 individual workers they say. I am sure we need to start pulling resources around here!

What are peoples thoughts on the exact sand, I have have 20 odd answers on this. Plastering sand, is it a must? Building sand and sharp sand seem to be used - so just what is the answer here. I have rendered some columns and a brick build coal-bunker in building sand and cement and that was probably 15-19 years ago - it's fine. The column I did is fine too. I know building sand is fine, and using some mortar as a bit of a render where you maybe make a bit up too much and "fix" something it goes on very smoothly, but it works...