MortarThePoint

This is cool, literally. If just looking to cool the floor, is it just a matter of having the right ASHP? Sending 15C water through the UFH pipes feels pretty low risk from a condensation perspective. If concerned by condensation on the manifold, one can always run a separate dehumidifier nearby or perhaps just a fan blowing over their surface.

What flow temperature do people use to cool their UFH? I'd imagine wanting to use a higher temperature (to avoid condensation) than an air blower would need.

Those are around 1.4 kPa of screed weight.

I agree and the leakage is what will allow it to 'breath' and push air in and out of the living area. Yes, it's nothing. I'd prefer that to the air going in and out.

But unless there is a sealant, it's going to leak out. If not, it would raise the floor by approximately (1/20) * 25ml / 7cm * 7cm = 1/40 mm which is admittedly tiny, but probably enough to open up an air leak to release the pressure.

I hate working this sort of thing out as sometimes ignorance is bliss. For a gas, pressure (P) is proportional to temperature (T) in Kelvin for a closed volume. Therefore if there is a dT there is a resulting dP. With the UFH off for some time the floor will be at the same temperature as the room. With it on, the temperature will rise above the room temperature by dT (e.g. rising to 36C giving dT=15C=15K). That's going to create a pressure difference of dP = (15/300) * 1Atm = 1/20 Atm = 5kPa in any air trapped below the floor. The weight of 50mm thick screed is around 2.4kg/m3 * 0.05m * 10N/kg = 1.2kPa. Presuming a continuous air gap under the screed that would lift the screed if it didn't leak out, so it will leak out. That's tiny you'll think, but most castellated panels increase the volume of air involved greatly. The volume of the castellation and ridge per unit cell is probably around 25ml (a shot glass) per 70mm x 70mm unit cell, so 5.1l per m2. So, a 20m2 floor will breath 5.1l per cycle. So what? I don't know, but I thought it was interesting. I had planned to glue down my castellated panels, but this makes me think of the air going in and out pushing out any warmed up fumes from the glue. Probably no biggy as the temperatures aren't very high. Has anyone thought about this before? @Nickfromwales you normally like talking sense against this sort of nonsense.

My manifolds are all going to be in cupboards, so is there any point in putting them in manifold cabinets? I can see them being useful if in a rental property (locked) or having the manifold in a room not inside a cupboard. The only reason I can think I could justify using one is to save the manifold getting knocked by someone tossing Henry (or Harry) into the under stairs cupboard. I don't think it would stop spiders of dust. Does it look unprofessional not to have one? What did others do?

So just to be clear glue only, no screws or bolts?

Poor guy, but hopefully he saw the funny side eventually.

I just found this link too: https://www.sunamoon.com/articles/fix-down-toilet-without-screws.htm CT1 looks good. I had a friend you sat on the toilet and it sank through the floor. When he subsequently flushed it went everywhere. All round at a new girlfriend's house. Didn't put her off though as they are now married.

Can a glued down toilet weather the storm?

Unless you're Jim in American Pie

I think I recall someone saying somewhere that they had glued their toilet to the screed rather than bolting it down. This is of interest to me for two reasons: Allows UFH pipes to pass below. In one place I haven't finalised the toilet position Safer over any membranes If glued down, is there any way of getting the toilet unstuck without smashing it if you need to remove it later?

Thanks Markc, Can you recommend a glue for metal Frame? I was worried that the smallest amount of water would cause the galvanising to whiten and I think I recall it being pretty easy to pull that off.

Do you think this would work with a metal frame partition?