MortarThePoint

I haven't got the tray yet and it could get trashed if I did

I'm avoiding Hardie Backer and the like. Also I'd tank the moisture resistant plasterboard

Yes moisture resistant plasterboard. I have the materials on site so that saves time.

12.5mm Plasterboard over 11mm OSB

I'm building the partitions of a bathroom and it's 1200mm wide for a 1200mm x 800mm shower tray. I'll be tiling onto the top of the tray (as shown below), but if I make the room 1200mm will the shower tray definitely fit or is there a tolerance that could catch me out. I'm hoping the tolerance is +0 / -Xmm so not allowed to be oversized, but hope isn't good enough. Does anyone know. I can easily wiggle an extra 3mm out of the plasterbard (1.5mm gap at each end) but wouldn't want to go much further.

Just to be clear, do you mean all cold pipes or just near the main feed?

Cheers Nick, even 15mm ones? So if not HRC do you only insulated your cold water pipes to stop condensation?

When insulating 10mm pipe do you just loose fit 15mm? Looks like insulating 10mm hot is of marginal benefit. It looks to about halve the rate of heat loss but I think it will cool to near ambient in half an hour (1.9C/minute at 55C, dropping to 25C in 31minutes). 15mm pipe does better at takes over an hour to get near ambient (0.9C/minute at 55C, dropping to 25C in 71minutes). I adapted the CheGuide spreadsheet (my changes in red including on 'Properties' sheet): Heat_Loss_Insulated_Pipe-10mm.xlsx

Not sure I follow. The insulation at ceiling level chiefly acoustic.

Does anyone know if these Hep2o manifolds, or any other hep2o manifolds, can have an actuator attached? I'm thinking like the standard actuators that Wunda sell (link1) (link2). The knob in the photo below doesn't look promising.

You link seemed to get broken. I guess this is the stuff you mean: https://www.amazon.co.uk/Galvanised-Steel-Fixing-Perforated-Builders/dp/B08M3L7YYZ/ Looks good with the PVC coating. I think this is one of those materials that once you start using it you discover lots of good uses for it. I've yet to use it but can already start to think of some other uses. How do you use that within a stud wall like I am looking to do? Do you secure a loop of it to the metal stud and suspend the pipe in the cutouts?

Is soft water just a preference thing? Plastic pipes are better with hard water that copper aren't they?

So do you just have the Kilmat wrapped pipe resting on the studs or do you use pipe clips screwed to the OSB in the bathroom side of the wall to hold it in place?

Talon do spacers, but it looks like a bit of a bodge: https://www.talon.co.uk/products/pipe-clips-and-accessories/pipe-clip-accessories/standard-spacer

The isolation benefit is reason enough to have the manifolds I think

I want to clip my 15mm and 10mm pipes to the underside of the concrete HCF flooring. I'll be using standard pipe insulation that has a 13mm wall. The standard clips, example below, look to leave less than 13mm between the pipe and whatever the clip is mounted on. Can anyone recommend on that is better for this as I don't want to have to kink my pipe for each clip or have the insulation pushing the pipe out of the clip.

An old thread, but a beautiful install and surely a standard to try to match with my own. Another benefit that comes to mind with using an isolating manifold is the possibility of adjusting flow rate to basins etc. What with the required water usage calculations etc, being able to set the flow could help reach a required total without putting restrictors in the pipes themselves or buying expensive taps. Did you add insulation to all the pipes after this photo was taken?

I suspect the top one (angled ply/osb) is easier if I install the insulation at rafter level first

I plan to use sheet VCL (green poly) to make the VCL around the loft room. I have shown it in green in the image below. Battens across the rafters for under rafter insulation (all insulation is mineral wool) provide a surface to staple the VCL to (tape over). I'll have to tape around where the VCL crosses each stud of the dwarf wall which will be a bit tricky, but OK. What I'm less confident of is how I deal with the big transition to wall plate (masonry walls). This is where the green VCL is crossing the 222mm high bottom chord of the trusses. Does anyone know what is normally done here? Just cutting a slot and flaps out of the VCL and stapling/taping feels a bit fragile. It feels like I should have something to support the VCL here. I can see two easy options with ~9mm OSB or 5mm ply. Shown below before and after adding insulation, though maybe the rafter insulation would carry on down before adding any sheet due to restricted access. In the top otption, the ply/OSB could be screwed in place and then sealed with Passive Purple meaning that the VCL itself wouldn't need to go down all the way, but may as well. Very time consuming though.

I was more thinking that my suggestion of a mixture of stripwood on the face of the studs and fewer sister studs would mess with centres, but it looks like there are some doubles etc anyway.

A bit of pocking around and I have found some (up to 4 way): https://www.jtmplumbing.co.uk/pipe-fittings-c433/hep2o-pipe-fittings-underfloor-heating-c999/hep2o-brass-manifolds-c661/hep2o-four-port-valved-manifold-15-tm-tf-fp-p21691/s27296

You could put strip would on each stud that doesn't have a strap and screw timber to the side of each stud that does have a strap. The problem with that though is it would ruin your centre to centre distances if they are already good.

Need to add appliances: washing machine, dishwasher and option for fridge

Interesting I hadn't seen that system before.

I'd like that. I haven't seen a Hep2O manifold that can do that yet, but maybe it's less widely carried that 5he simple non-isolating manifolds.