I am installing wet underfloor heating in a new extension. The existing kitchen already has UHF so I have some experience with a simple system, but I want to check as much as possible before I make expensive mistakes.
I am planning 3 zones to be screeded (by a professional, not me) on the ground floor (1 of which will be a wetroom), the existing zone and 1 upstairs zone (another wetroom) with a biscuit mix. For the falls in the wetrooms, I expect the screed to be laid with the required falls and figure I can do the same with the biscuit mix - although I wonder how dry it needs to be, and whether it'll hold it's shape.
1. For the wetroom on a biscuit mix I've been advised to fix a plywood covering over before tanking and tiling to prevent tiles popping with movement. This feels counter-intuitive as it will insulate, but I suppose it solves the problem of tanking/fixing tiles on a loose material. Is this correct? What thickness do I need and how should I secure it? Screwed to the joists?
2. For the biscuit mix, what sand should I use? I'd think sharp sand for a concrete but if it's not for structural strength, would builders sand have less air between particles and therefore better conduction? Incidentally, I happen to have a load left over from another job
2. How high should I fit the manifold? I guess it should be the highest point to avoid trapped air in the loops. However one zone will be above it - I suppose I could put the manifold in that room but only if it's a big deal. The utility room below is a much more suitable location otherwise.
3. I need to extend the kitchen zone pipes to where the manifold will be and don't like the idea of the join being buried in a screed floor. I have a route in mind where the pipes are hidden in stud partitions, thinking it would be easier to access through the plasterboard if needed than the concrete. If the manifold is fitted high on the wall I could probably avoid any possible air traps in the loop.
4. Not specifically UHF related, but I have a couple of concerns about designing a wetroom. It is a rectangular room with shower at one end and toilet and basin towards the other. I figure the whole room should have a fall towards the shower drain. How do you deal with a toilet (and possible basin pedestal) on a sloping surface? Is it just too small a slope to be a problem? Having tanked walls and floor before tiling, is it not a problem securing fixings with screws that would puncture the tanking?
I am planning 3 zones to be screeded (by a professional, not me) on the ground floor (1 of which will be a wetroom), the existing zone and 1 upstairs zone (another wetroom) with a biscuit mix. For the falls in the wetrooms, I expect the screed to be laid with the required falls and figure I can do the same with the biscuit mix - although I wonder how dry it needs to be, and whether it'll hold it's shape.
1. For the wetroom on a biscuit mix I've been advised to fix a plywood covering over before tanking and tiling to prevent tiles popping with movement. This feels counter-intuitive as it will insulate, but I suppose it solves the problem of tanking/fixing tiles on a loose material. Is this correct? What thickness do I need and how should I secure it? Screwed to the joists?
2. For the biscuit mix, what sand should I use? I'd think sharp sand for a concrete but if it's not for structural strength, would builders sand have less air between particles and therefore better conduction? Incidentally, I happen to have a load left over from another job
2. How high should I fit the manifold? I guess it should be the highest point to avoid trapped air in the loops. However one zone will be above it - I suppose I could put the manifold in that room but only if it's a big deal. The utility room below is a much more suitable location otherwise.
3. I need to extend the kitchen zone pipes to where the manifold will be and don't like the idea of the join being buried in a screed floor. I have a route in mind where the pipes are hidden in stud partitions, thinking it would be easier to access through the plasterboard if needed than the concrete. If the manifold is fitted high on the wall I could probably avoid any possible air traps in the loop.
4. Not specifically UHF related, but I have a couple of concerns about designing a wetroom. It is a rectangular room with shower at one end and toilet and basin towards the other. I figure the whole room should have a fall towards the shower drain. How do you deal with a toilet (and possible basin pedestal) on a sloping surface? Is it just too small a slope to be a problem? Having tanked walls and floor before tiling, is it not a problem securing fixings with screws that would puncture the tanking?
