Loz

Thanks for all the replies, I have been doing quite a lot of reading in between posts, seems banging it up to 60 on the water temp and then turning it off ready for the tilers could well have been a mistake - the room never got above 25 degrees during all of that as an aside. I have been on trustpilot and read reviews of the moduleo LVT flooring and they are pretty bad - in fact appalling, then swapped to karndean which is a more expensive LVT and they were similarly bad - I know installation is likely to play a part as is people being more likely to leave a bad review but a hard sell reading those. Given I have the porcelain tiles paid for at property with tile company refusing to take them back (been more than 5 weeks - their policy and they are not budging) I am leaning towards finding a solution for them. That solution looks to be a decoupling matting and on internet found ditra 25 for £750 - durabase ci a bit cheaper but forums people seem to stick to the tried and tested ditra 25. I am tempted to risk it, wich I knew if crack was caused by movement or thermal shock of some kind - UFH been on for two months and crack only showed up when cold after weekend so no way of knowing I guess - could be the dry weather and the foundations settling, rep seemed to suggest if movement between the sub floors then matting won't help - thought would help a bit - any further thoughts greatly appreciated as will be pretty depressing to be a good few thousand in and a crack opening up across middle of room in most high traffic most visible area, Many thanks Loz

My partner always wanted LVT ! I always wanted porcelain tiles largely as can't get my head round vinyl but mainly as thinking about ancient vinyl flooring from when I was young, also was thinking porcelain would hold heat well with the under floor heating and wear better, the Moduleo LVT been looking at in Transform range does say 20 years on wear but assume would be longer but guess a relatively new product, really don't know what to do as guess very difficult to tell whether is a thermal or movement crack, strange that crack only just showed up but chance it would diminish if turned heating on an experiment want to do after guy has seen it tomorrow. Just spooked now about movement and potential cracking elsewhere as there are other large openings into old house where we have historically had problems, to be honest deep down wish gone LVT from beginning as had a mare with tile company even before today. Loz

Thanks for replies, I guess the thing that is spooking me is that the crack is on the line between the old and new extensions where movement between two sub floors was likely. It is also an area where there is no underfloor heating, if I caused the problem by whacking it up too much in final week which is I accept a possibility then wouldn't it crack where there is the under floor heating rather than where there isn't - very new to all of this as you can tell. Managed to speak to a dura mat technical person that from description said sounded like movement rather than thermal shock and he has very kindly offered to take a look in morning, if is movement from sub floors said mat wouldn't help but a movement joint might but crack is not straight. Duramat for whole area is £1200 plus extra labour for sticking it down and extra adhesive on top - probably the same as hit I would take ebaying the tiles - be interesting to see what he says tomorrow - will update, thanks for all help so far, been a bit of a nightmare, Loz

Hi yes there was a foam strip all the way around the perimeter, been trimmed down now to floor level so not showing, strange in a way the crack is where there is no underfloor heating between the two zones, bit concerned I caused the problem by whacking it up to max (60 degrees) last week to dry and get last bit of drying done but after 5 months thought would be okay. Tiler has spoken to the matting people and they are saying don't guarantee it so he is not happy to do it so a bit snookered now. Tiling company won't take the tiles back as been more than 5 weeks so truly having a mare. Tilers advice is to ebay them and go with luxury vinyl tiles throughout. Not been a good day as all the other trades were lined up after this. Cheers, Loz

Thanks for quick reply, tiler was going to use flexible adhesive, been looking at the decoupling mats - presume would need to do whole floor rather than just the crack ? They do add up a bit, my only other option is to return the tiles if I can and use a different flooring type - luxury vinyl tiles guess would never crack, bit of a nightmare all round - tilers feeling is whatever do there is a good chance of a crack in 60x60 porcelain tiles and couldn't be in a worse place from a looks perspective as right in middle and won't be covered by anything, Thanks Loz

Hi, Had liquid screed poured about six months ago, was sanded a few weeks later, under floor heating was commissioned about 2 months ago and turned it up slowly and all been looking good and moisture was getting to the magical 0.5 so could tile. With a week to go was still reading 0.7 in places so decided to give it another week and given such nice weather had all doors open and whacked heating right up to max. Turned the underfloor off Friday so could be primed Monday (yesterday) and noticed a crack running across floor between the two heating zones underneath the opening which joins a new double height extension with existing single storey extension. Hadn't noticed a crack before and sure appeared when cooled down over weekend (wasn't at property). Plan was to use 60x60 porcelain tiles - tiler turned up today and said not happy about crack and said whatever he does reckons will case tiles on it to pop or crack and has said to use a different flooring - luxury vinyl tiles. Problem is all the tiles are here and kitchen goes in Monday. Been doing tons of stressing and reading, just not sure what sort of crack dealing with - thermal, movement, shrinkage - new to all of this, been reading about decoupling mats but tiler didn't seem to keen. Any advice greatly appreciated, reckon the crack is about .5 to 1mm. Pictures below Loz

Thanks both for replying, was hoping general opinion would be that it is okay, system has been filled so no leaks, was just concerned could be a weak point over time but sounds like will be fine to leave as is, I think there is a very slight bend in the pipe but could have probably benefitted from a bit more, Many thanks, Lawrence

Here is picture of pipe coming out of top, there is a little bend but where exits valve is at a bit of an angle....

Hi, Plumber was doing bathroom today and was plumbing in thermostatic valve for shower in copper, all looks good other than the pipe that comes out of the top and runs up into attic for rainfall shower head. As there was something in way pipe is running at an angle - probably about 5 degrees, hot and cold filled and no leak but could this cause a weak point further down the line or doesn't it matter ? Will be a tiled wall ultimately so a pain if ever leaked in future. Just looks weird as every other pipe goes straight into its housing other than this one and can't help feeling it should be straight. Guess only solution would be a couple of right angle bends close together - not sure of that would reduce flow at all as want max flow to the shower head or tp bend the pipe but bit late for that now as all hooked up. Any thoughts greatly appreciated. Many thanks, Lawrence

Thanks for that, think that was what electrician was expecting, Lawrence

Magic, thanks for clarifying both on the controller for manifold, will try and go through it all with both of them on site, still not sure on this side of it: 'Could they connect the Honeywell T4M which is just for open therm boiler to the 3 channel timer ? Reading literature seems to suggest this should be going to direct boiler and is programmable. If I had a two channel timer for tank and UFH and then the T4M for the boiler how would they know about each other to operate the 3 2 port valves correctly - as you can probably tell I do not really understand this.' Many thanks, Lawrence

Many thanks for both taking time to reply, I have an electrician and plumber who will both be on site tomorrow and was trying to get head round it so can ask the right questions as they kind of leaving the choice of programmers/thermostats to me. The electrician has run wires for the underfloor heating thermostats back to the UFH manifold which is in the garage saying there will need to be some sort of controller there to open and close the manifold valves. The plumber seemed a bit confused by this thinking they should be going to the airing cupboard where the two port valves are, not sure who is right here. Could they connect the Honeywell T4M which is just for open therm boiler to the 3 channel timer ? Reading literature seems to suggest this should be going to direct boiler and is programmable. If I had a two channel timer for tank and UFH and then the T4M for the boiler how would they know about each other to operate the 3 2 port valves correctly - as you can probably tell I do not really understand this. Many thanks, Lawrence

Hi, Been a great forum for all my problems thus far but managed to completely confuse myself over how to control heating/water. In midst of a renovation and what going to end up with is two zones of underfloor heating downstairs and the rest of the radiators separate. Gone for a Baxi 824 system boiler (which is open therm compatible) and unvented gledhill tank. The boiler is in the garage next to the manifold for the underfloor heating and the tank is in airing cupboard where the ancient timers/controls are with a thermostat nearby. Can run wires to anywhere at moment and wanted to go for a wired system. Don't really need wifi/app access or anything and wanted to avoid anything wireless. Now this is where completely confused as started looking at what to use to control it all, plumber normally uses nest/hive with wireless stats but as above wanted to go a bit old school and have everything wired, did want to take advantage of the open them capability of the boiler. Looked at all the major manufacturers Honeywell, Drayton, Nest, Tado and more but struggling to find a wired solution that can control 3 channels (open them boiler, hot water and 2 zones underfloor heating). There are I believe 3 two port valves going into the airing cupboard where the tank is. Found this programmable stat Honeywell T4M which is open therm and wired to boiler - but then how do I control the underfloor heating and water tank ? Can I just add a 2 channel timer for those but how would they link to thermostats and how would it interact with the T4M which is linked to the boiler. I really am confused. Found this 3 channel programmer Horstmann Plus 3 Channel Programmer H37XL but how does that then link into thermostats and possibly achieve open therm. As you can tell I am a bit clueless on this side and some basics would be most useful. Many thanks, Lawrence

Thanks for clarifying

Thanks for all replies, sounds like a need to nudge plumber into fitting an external expansion vessel - for my info is the external vessel in addition to internal one in volume or does the external one mean internal one is redundant ?

Last question - Promise ! Looking at the Baxi 824 it has a 7L integral expansion tank - the megaflow 28 and platinum 32 have 10L, I have 13 radiators and bit less than 40m2 of underfloor heating and pipework running every where - is 7L big enough - not sure how to guesstimate ?! Many thanks, Lawrence

Many thanks for quick reply, much appreciated, gives level of confidence in the 24kw model, Cheers, Lawrence

Hi, My original thread went off track a bit but I am back to my original problem, I need to chose boiler size by Monday, the plumber is not going to do any heat loss calculations or do anything to work out accurately so I am on my own other than the expertise of this forum. The plumber had said he thinks the baxi 824 (24kw) system boiler is fine, annoyingly they don't do a 28 in that range. Could go for a 28kw baxi megaflow but an older boiler with less of a guarantee. There is a Baxi platinum but that only comes in a 32kw model. My preference is for the 824 24kw boiler if can cater for the house (there will be no further additions once renovation is complete). Here is summary of the house: House is 1955 detached house with cavity wall insulation, it is 4 bedroom two of which added to new building regs so well insulated. House is not particularly cold in that there is only one room where radiator is on full in winter. At the end we will have 13 radiators, many of them quite small, have done some calcs and KW of them all seems to add up to on 12kw - seems low as guidance seems to be 1.5kw per rad but a few of them are towel rails and small radiators. Worse case guess would be 16kw. We will also have 2 zones of under floor heating first zone 1 is 13m squared and second zone 2 is 24m squared using 16mm pipe. We have 3 showers but 2 electric so only one will be running off tank, did consider combi but would be long way from where water needed and decided on the system approach with unvented tank in centre of house. We will be going for a 210 litre indirect unvented tank from gledhill - https://www.gledhill.net/products/unvented-cylinders/stainlesslite-system-ready-indirect/, the manual lists the 210 tank having a primary coil rating of 20.5 kw - not sure if reading that correctly as cylinder calculations normally allow 3-5kw. Any thoughts greatly appreciated..... Lawrence

Thanks for response, will definitely ask about the underfloor heating separately from radiators. Getting gas to the current cylinder position would be tricky as would the flu as will double check but no easy access to external wall and upwards would be a problem but will take a look this afternoon.

Wow, thanks for detailed reply, that really does help explain things, arms me with some questions for the plumber on whether to go up to the 28 to run the two simultaneously, we will always likely have the UFH and radiators on at same time so guess no need to isolate although has made me start to think on that as believe UFH takes longer to heat up so likely would want that to come on earlier - mmm not sure now. On the Combi question that was original plan, only problem we have is the boiler is in the garage and whilst close to kitchen is a long way from the upstairs bathrooms so was concerned on how long would take hot water to get to the basin taps. The tank is situated between the three bathrooms giving quick hot water and also my partner really wants the luxury of pressured hot shower which will be the main one fed from the tank, I'll be honest I am a bit torn over the whole setup now. We do have an airing cupboard for tank to go in (replacing ancient one connected to tanks in loft which had to be removed as part of renovation although could conceivably be recommissioned elsewhere in loft). Many thanks, Lawrence

Hi, In middle of renovation, at the end will be a 4 bed detached house (1950's) with reasonable insulation (new extension will be to new regs). There will be two electric showers and additional one from the hot water tank. There are two zones of wet underfloor heating (zone 1 16m squared, zone 2 24m squared). Going for a system boiler with unvented indirect 210 litre cylinder. We have 13 radiators. Plumber wants to go for a Baxi megaflow which looks good but has been suggesting 24kw model, looking online that looks underpowered, they also do a 28 and 32, a friend in similar setup but with much larger tank has the 32. What would people recommend in this scenario ? Any help greatly appreciated Many Thanks, Lawrence

Hi, Need to re-route gas as part of renovation and best solution is to run tracpipe from meter to new boiler in garage, it would mean running pipe in ground (following recommendations/regs on depth/covering) through the gap pictured below which is 950 at narrowest point : Are there any regs falling foul of with that ? Found this in tracpipe document: On first paragraph guess okay given gap is 950 although do have to squeeze drainage pipe for surface water through there as well - guess not acceptable to go over top but could come off wall 250 for tracpipe, have another 250 and then lay the drainage pipe and then still have 250+ to wall although probably not foundation - not sure what regs are on the drainage pipe distances from foundations. The second paragraph worries me although another option is to move the meter into garage which is expensive and not ideal place in the garage and the gas company were going to run down side of house at similar sort of distance looking at with proposed run and surely that must happen a lot. Presume in this case the 'under' hopefully literally means underneath. Nothing else on the run other than further on run needs to go past manhole over sewer line (sewer line 1m down) but again should be able to keep 250 away from manhole. What do poeple think ? Should I be looking for another route although this gap would be the easiest run from meter to boiler (nothing else in house will be gas). Any thoughts greatly appreciated , Lawrence

Many thanks for reply, it's a liquid screed so sounds like the tape is enough, cheers, Lawrence

Does appear to be polypipe as that is 18mm pipe that does come up with googling, will try and ring some suppliers today to see what they say, will also check that edge insulation is going to be used as none in the room at moment : https://www.colglo.co.uk/product.php?product=UFCHF1500 - seen some sites where the block insulation also goes round the edge - is that needed or is the blue tape in the link enough ? Many thanks, Lawrence

Thanks for taking time to reply, have spoken to plumber this evening, it is 18mm pipe and he says always uses 200mm spacing so guess just have to run with that, doesn't seem to be any design and said we can work it out on Friday when on site. He did say would normally run right up to the kitchen units which doesn't sound quite right, he has done quite a few installations and is also doing boiler/rads/plumbing for which he comes recommended but the underfloor heating does seem a bit hit and miss.