CotswoldDoItUpper

Ok laying 16mm slimline pipes on 150mm centres (but if this isn’t a good plan then let me know! to start with: zone 1: 13.5sqm 100m zone 2: 40sqm 270m zone 3: 7.8sqn 52m zone 4: 7.8sqm 57m zone 5: 7.2sqm 48m Added in future: zone 6: 20sqm 135m zone 7: 15sqm 110m zone 8: 90sqm 70m thanks!

Ok so I’m STILL trying to plan UFH. I’ve been told by a number of different ppl (from suppliers to you lovely lot on here) totally different things re. Length of pipe run. my longest loop could be 270m. Is this too long? If I split it in to 2 135m runs is this still too long? please help before I go completely mad!

We have had switched 5A circuits with plugs in every house we’ve owned and also extended the circuits/moved the sockets to have them where we want them. Particularly useful in bedrooms with 2-way switching from the door and by the bed.

Not yet. I have a Jewson’s one tho!

There are air bricks around the perimeter below the level of the joists. Hopefully this will be ok! So you need to make sure they are exposed to the draught. If you have any standing water or dampness under there, it will be at least as bad. Unless you seal it entirely and makes sure the joists are far enough inside the insulation layer to be kept warm and dry - which is the more unusual technique of filling the whole void with Leca or Polybeads.

We weren’t overly keen on the weld and the mechanism felt a bit cheep on the showroom window. For the price it was good value, maybe we just need to spend more! Also, SWMBO didn’t like the colour choices. I just do as I’m told. @Lorenz that would be great if we could easily change our openings. It’s a renovation so mostly fixed sizes. @Ferdinand how do you find local manufacturers? Is google the best option? @Russell griffiths we might not get such a good discount as we are doing things room by room. As you say, worth a try though! First window is a 500x1000 single opener flush fit supply only: Windowsanddoors.co.uk : £176 Modern uPVC : £212 Just value doors alu : £555 Just value doors uPVC : £431 Just doors uk uPVC : £294 windowsarchitects.co.uk timber/alu (not flush) : £263 Seems a huge variety. Any experience of any of these? any other suppliers I should add to the list?

… as a budget window supplier? We aren’t after 17G windows with a negative U value (!), just something that’s reasonable value 2G in uPVC or at a stretch Alu. Preferably a flush casement. Almost certain we can’t afford alu/wood but more then happy to be proved wrong. Went to see https://www.modernupvcwindows.co.uk yesterday and although the price is v keen, the product definitely reflects this. Not one for us I don’t think.

We’re starting by just laying the insulation, sub floor pipes and membrane/tiles. Will actually commission it when we can add bits. if we lay PIR between joists, 18mm chipboard over then lay the 20mm routed insulated boards for pipes over the top will that be enough to avoid cold bridging through the joists? Think this is the way we’re going to go if it does. tia!

That’s a great shout with seconds and co! Will definitely go for that. Need to do my garage too so that’ll be perfect!

So I’d have 100mm PIR below and then 100mm rock wool or similar? Surely the 70mm PIR would give better results? Happy if not, saves a bit of cash!! How on earth would I hang rock wool under the PIR?!? Seems like madness!

Looking for PIR sheets and cant see any difference between IKO Enertherm, RECTICEL EUROTHANE GP, Celotex and Kingspan. Apart from the price. IKO Enertherm seems significantly cheeper at about £55/ 1220x2440 sheet as opposed to £75/sheet for the others. Am I missing something?

Ok so it transpires that my joists are 100x50 at 400 centres but the gap underneath is 550 before I can see what looks like a plastic sheet on top of concrete. I guess I could therefore fit 100mm under and perpendicularly to the joists and 70mm in between solving the issue of the cold bridge? Then still have space for a spreader plate and pipe work for the UFH. Does this make sense? Is there a scenario in which I could use mineral wool to make this cheeper? Can’t work out how I’d ‘hang’ nearly 300mm of mineral wool from the joists. also, there are 15mm copper water pipes atratched to some of the joists. How do you work around them when laying insulation between the joists? thanks all, nearly got a plan!

@PeterW guess I’ll also need an expansion tank for that too? What size do you think? This is getting more and more complicated (and expensive!) by the day!

@PeterW on that note, how big should a buffer tank be? #CluelessNewbie

thanks, think that makes sense! Or I’ll get a plumber to do it. DHW is currently ask LPG combi but will switch to a cylinder when switching to ASHP. Think this all makes sense in my head anyway!! Such a brain fog trying to work it all out.

I was thinking of having 2 in parallel as a back up for the ASHP anyway long term so that was the only logic. Other then that it’s only half the house and no HW so assuming we had a 16kw ASHP and therefore only using 1/2 (half the house) that’d be 8kw so 6kw not far off. Have I got this wrong? Happy to be corrected! Have no idea how to spec/cost up hooking to existing lpg combi with a buffer! Every day is a school day!

Thanks @MikeSharp01 we have decided on going for spreader plates all over to keep room heights as much as possible. Zone 2 is going to be about 250m pipe, so it’s going to have to be a big pump to cope with that! What counts as a ‘big’ pump? How are they measured? Guess it’s not just size! Most sites say max run of 100m but I thought that that might be marketing to get you to buy an extra manifold or other accessories. If 250m is ok then we’ll go for that!! We have an air gap and soil/rubble under joists - hence the need for insulation. We will have to have joints unfortunately due to the phasing of the project so will make sure these joints are easily accessible in case of emergencies!!

Thanks @Cpd definitely a consideration the cold bridging yes. It’s a 1800s cottage so there will be lots of other insulation compromises along the way. It’s about doing what’s the most appropriate option I think. Will eventually (next year prob) be ASHP I hope, but in the meantime a couple of Willis heaters will do the job of warming water. @Mr Punter Joist depth is variable around the property but generally 150-200 at 400 centres. Pollythene sheet sounds v cost effective, does the vapour layer not have to be breathable? Have read about battens but sounds fiddly and even more cost to the already more expensive PIR option. Is PIR worth the extra outlay over mineral wool or EPS?

Hi Wizards, We’re about to start ripping up floors ready for insulating between joists but have choices abd can’t decide on best one to use. Cost is a major consideration but if one system is significantly better/easier to fit then we’ll take that into account too. 1: PIR expanding foam and tape 2: EPS expanding foam and tape 3: mineral wool laid in net ‘hammocks’ (only what I can think to describe it!) covered with vapour barrier. other things to consider: options 1&2 will be covered by 18mm ply/chipboard followed by UFH and tiles option 3 would use spreader pates, notch the joists and then vapour membrane all covered by 18mm ply/chipboard and tiles. any experience with any of the above greatly received so we don’t fall into common pitfalls! TIA!

Hi All, Jumping in here needing to ask about UFH. We will be (long term) installing an ASHP to run UFH but we cant afford that yet so in order to make the house reasonably decent to live in were renovating and therefore starting by installing the flooring inc UFH. It will be powered by willis heaters (thanks to BH for that suggestion!) in the meantime. We suspended timber floors on the GF and therefore as I see it have 2 options (please correct me if I'm wrong or there is a better way!). Option 1: a- remove existing floor coverings and floorboards b- install 100mm PIR in between the joists, expander foam gaps and tape c- 18mm ply over d- lay pipe insulation boards and install pipes e- tile directly the boards (no screed) with flexible adhesive and grout. We will be using natural stone so may need a decoupling membrane. Any advice? Option2: a- remove existing floor coverings and floorboards b- install netting between joists and fill with rock wool or similar c- lay pipes in spreader plates (prob ok in the 1980s part, what happens in the 1800s part when the joists won't be regular?) c- 18mm ply over d- tile over with flexible adhesive and grout. Other questions: - We will be doing zones 1, 2 and 3 first. Is zone 2 too big be one circuit? the room is approx 5 x 8m (typo on the plans - 41sqm not 31) giving a pipe run of about 200m. Think I'll have to split this into 2a and 2b - Is there an issue with having accessible joints in the UFH loops? We need to run the pipes from the manifold an area (prob in the corner of zone 5) ready to do the lower levels when funds allow before finishing the floor in zone 3. The unused pipes will then be capped ready to take the extra loops when ready. - There is a 750mm difference between zone 3 and zone 4, with zone 4 etc being lower. Do I need a second manifold/pump etc for the lower level or can it be run off the same unit? - Is there any benefit to either option above? I can see pros and cons of each but no definite winner. Head-height is lower then standard (2.3m) in the 'new' bit and 1.9-2.2 in the 'old' bit, depending where you stand. Think it might be option 1 in the new bit and option 2 in the old bit due to spreader plates not fitting, but I don't like the idea of having a big chunk of ply wood soaking up all the heat from the pipes if they're between the joists. Thanks for taking the time to read though this, any advice/guidance/abuse welcome! CDIU

Hello All, Thanks for letting me join to ask endless stupid questions. We've bought a 1800s cottage that was greatly extended in the late 1980s and not touched since. Previous owners lived here 35years and the owners before that moved in in 1929. It has a stunning 'old person' garden (steep learning curve!) and plenty that needs updating inside the house and a good size detached garage/workshop that will also be converted one day to a 1-bed annex. Plenty to be getting on with. TIA for your patience. CDIU