ashthekid

Is it normal to insulate standard 4 inch waste pipes from sinks/showers/baths that are hidden in joists and cavity spaces in any way? Only against noise. If yes, what do you recommend?

I’m told that Grohe’s new Rapid SLX concealed framed cistern is the quietest cistern on the market now so it seems very appealing. Has anyone had one? Is there a difference in quietness or is it a bit of a sales gimmick? And this may be a silly question but is this cistern compatible with any wall hung WC that is attached to it? Or does any brand WC like RAK or Duravit fit onto this new Grohe concealed cistern?

There are no ventilation blocks/slots in the Listed part of the wall. At the top, between where the Listed wall is and the newly formed timber frame is a newly created box gutter made it of ply with a resin fibre layer on the inside of the gutter. Due the Listed wall being so old and not straight we’ve created a header course on the top of the brick wall and put a lead flashing flap down into the box gutter so not really a ventilation gap as such but because the lead isn’t sealed to the box gutter I guess there is the tiniest of ventilation somehow? The inner side of the brick wall at the bottom is a mixture of exposed brick in most parts and then just old build up of plaster or cement with a small part still showing some bathroom tiling on. A very small lip of damp course plastic that flaps up from where it was laid underneath the new concrete slab. I would have ideally liked that to flap up the wall a lot higher to stop any transfer of moisture from the brick wall to the timber frame.

A very old uneven brick wall dating back 100yrs+ with a large empty cavity space(100-200mm), then a new timber structural stud wall(sat on a new concrete slab) filled with PIR insulation in between and both sides of the studwork. To stop any kind of dampness or moisture inside this cavity space, what is the best thing to do? I say this because we haven’t installed the PIR insulation yet so I have an opportunity to do something now to prevent any build up inside. We aren’t airtight yet(85% tiled) and have had a lot of rain recently which may or may not be confusing the situation. The floor and lowest part of the brick wall looks to be very damp. 1) Do I just leave it knowing it may be fine and I’m just overthinking it? 2) Do I make sure the cavity space is well ventilated somehow(cannot touch the brick wall because it’s Listed)? 3) Do I fill the cavity space with something that helps prevent moisture but could be costly due to the size of the cavity space? 4) Is there an alternative solution I haven’t thought about yet?

Any thoughts on this?

We have a plant room created big enough probably for 2 slim but tall cylinders. It’s also housing the UFH setup. It’s going to be rare for there be any more than the 4 adults & 1 child - i.e guests staying. So demand will be lower than the predicted amount in a 6 bedroom/6 bathroom I would say.

That Sunamp setup looks very interesting and a perfect solution. Essentially like a combo boiler with instant hot water with no cylinder and looks like you don’t lose any water pressure which is a bonus. Does anyone have any experience using a Sunamp system? Looks like it works well with Solar PV. What’s not to like. Is it expensive? Could we have a Sunamp system alongside a backup 300l cylinder perhaps for when we have people staying over knowing that water demands will increase temporarily?

I’m not sure we would have room for dual cylinders to be honest but I do like the idea of that. ASHP heating of DHW and UFH with addition of Solar PV with the Eddi diverter to provide any unused electricity to the hot water cylinder directly. Occupancy wise there will be 4 adults and one child. Mainly showers only to be honest, only baths for the child but those are only small shallow baths so not your normal adult bath usage. The plumber has suggested a 300l which is now sounding like an inadequate size after what has been said on here. Perhaps a 500l would be sufficient capacity to safeguard myself, knowing that on the odd occasion demand would be higher and somebody would just have to wait a little bit before having a shower.

What would be the recommended size of the cylinder for a 6 bedroom, 6 bathroom property. Specifically with 4 showers, 2 bathtubs, 10 sinks. I would prefer to oversize it to be on the safe side but am curious to see what people suggest.

Am I correct in assuming that if you timber batten 25mm over insulation PIR board and then apply the plasterboard to those battens you stop the possibility of nail/screw popping on the inside of the plasterboard coming through the plaster?

They are proper joists. Ok so extra joists over extra noggins then? the joists are pretty close together already, I would say less than 400mm on some of them. It’s an odd shaped property, not that that should make a difference.

I’ve noticed a bit of bounce in two rooms upstairs during our build project and am thinking would doubling up on noggins between the joists help to stop or reduce this bounce? Chipboard flooring has been laid and screwed in. Nothing has been added to the joists underneath yet so that’s why I’m asking now while it’s still possible to up the noggins number. What else could be done?

No alternative outlet sadly, this was the only option. It's quite a wide cavity space that the pipe is in and it's just by the living room kitchen area so I just want any noise from rainwater to be at a minimum. I have a large roll of TXL foil insulation that the builder said I could use to wrap it with but I'm not sure it will do the job very successfully. I'm trying to get hold of RockLap quickly though, that's likely to be my next problem. And what thickness of RockLap?

What product would you recommend exactly for insulation inside around the downpipes? Mine are all already installed and ready to be insulated with something. I just want to make sure I get the right product and don't waste money on something else that is awful and inefficient at soundproofing and thermally protecting from any moisture/condensation on the internal pipework(which is soil pipe size) before the next wall layers go on. Apart from the Rocklap I suggested in the beginning, is there anything else similar and possibly cheaper?

Or perhaps this Superfoil wrap will work better? @ToughButterCup get your own thread ??

My cavity space is unusually massive because of structural specifications so am using a 110mm pipe. So nobody has used the Rocklap that I attached earlier? I’ve never heard of it before but it seems good on paper.

I have a couple of box gutters that are draining internally through a cavity wall space. I know that isn’t ideal but had to be done because of various party wall conditions with the neighbour. I want to insulate this pipework to protect against acoustic potential and also to stop any potential condensation that maybe produced because of it being located in a cavity space. Has anyone used Rocklap before or an alternative product or maybe a different idea to insulate it quickly and easily? It’s soil pipe size. I attach some details on the Rocklap.

@A_L the glazing wall is pretty much East facing. Do you think I have a particular glazing style? i.e. triple glazed?

Just how important are purlins in a timber frame roof & wall structure with vaulted ceilings and two king trusses in?

What do you mean by “no heat” value?

So to give an update, I’ve decided to upgrade the PIR underneath the rafters so now I have the 100mm in between the rafters, then 50mm on top and then another 50mm in the opposite direction to creat a better airtightness(I think) with foil taped joins. Do you think that 200mm total in the roof layers will be good enough to help with my thermal insulation protection?

@PeterW No mesh matting that I can see being used, just a RES-TEC primer onto the ply then the resin along with powder hardener. I’m assuming mesh only really gets used in larger flat roof type surfaces, rather than small box gutters like this? Access and maintenance from a ladder either side. There is only approx 2m that would be trickier to access because of neighbouring property adjoining the party wall.

Update: box gutter has been created with ply and now this product below is being used to line it. FlexiTec by RES-TEC. Anyone used it before? Is this the GRP that was suggested? Taken from their website: The Flexitec 2020 System by Res-Tec is a flexible, single resin GRP system with full overlay and new deck capabilities. Combining the best elements of fibreglass with the versatility of overlay systems, no other flat roof solution performs at this level across so many applications.

@Dan F I’ve seen a few options(screenshots below) on a specialist soundproofing website but after everyone’s comments I’m beginning to think it’s not worth it. I have issues with head heights too in this project so can’t go crazy thick on floor or ceiling joists. I’ve seen this 5mm rubber matting(below) that is good for effective soundproofing a little bit. Worth the investment?

@nod Unfortunately all timber stud work is up already so can’t have MF studding. Have considered res bars but will likely have battened layer. In some key areas I may decide to put some of the foam backed plasterboard which sounds like it’s quite effective. And then just fill the cavity space between the stud walls and floor joist between ground and first floor.