JohnW

You mentioned that you have a 100mm slab with the UFH pipes within, would you mind sharing the full floor build-up please?

Thanks @Nickfromwales & @JSHarris...I used to consider myself a reasonably intelligent person, but having read that thread I realise I am walking among giants! I think my floor slab will have fully heated by the time I absorb all that information.

Thanks again @JSHarris, that's very useful information. I'll spend the evening trying to calculate the sweet spot of insulation thickness for my build. As you very clearly know your way around the thermal calculations would you mind if I re-position my original question?... The original question was regarding the concrete screed, and I believe the thinking behind the inclusion of 10mm stones is to increase the thermal mass and therefore ability to retain heat within, allowing it to slowly release over a longer time. My builder has suggested using 50mm of liquid screed (Cemfloor Liquid Screed C20/F4) instead. I can see and understand the benefits of the liquid screed during installation, however what I can't see is whether it will be as efficient and effective as the concrete in heating the house. Any thoughts/calculations would be appreciated.

Thanks @JSHarris, what depth of insulation would you recommend?

Thanks @Dudda, we plan to finish the floors with tiles. We have been advised that using the 125mm will achieve a u-value of 0.15, however I accept your point about increasing it to 150mm. One of the reasons for the 2 layers of insulation is to be able to accommodate the first fix plumbing, e.g. areas that have pipes will be built-up as 50mm below pipes, 50mm beside pipes and 25mm above pipes, giving a total of 125mm to match areas that do not have pipes (50mm + 75mm). Thanks for the tip regarding the tape/polythene for the joints.

Thanks @jack ground floor build-up is... (from top down) 100mm concrete screed (with wet UFH pipes embedded) 125mm foil backed polyurethane (2 layers 75mm and 50mm with staggered joints) DPC (1000 gauge polythene) sub floor

I will be installing wet UFH and I have been advised to lay 100mm depth of 35N concrete screed (sand/cement/10mm stone) laid as a wet mix with a brush finish. The thinking behind it is, that the stone increases the thermal mass of the floor (more so than just sand/cement). This doesn't appear to be a common screed. From reading various threads on here, it appears that most people are using either liquid screeds or sand/cement. Have any of you used such a concrete screed or can you advise?

RTU guy said it only needed to be 50mm and it was for UFH

@Shell820810, your stairs are exactly what I have in mind for mine. Can you share some details about price and supplier please?

The RTU guy who gave a talk at the Self Build show said the Ultraflo screed (similar to the Cemfloor) would cost "around £14/m2".

Thanks @vfrdave, did notice the cemfloor stand but didn't have the wit to talk to them!! I thought the show was good, but to be honest it has raised more questions than answers for me...questions that will of hopefully be answered somewhere in this forum at some stage.

Hi @Weegaz can you share the cost of the RTU Ultraflo and why you chose this over regular sand & cement screed? Also have you got UFH in the screed? The reason I ask is that I sat in on a talk about Ultraflo at the Self Build show in Belfast on Friday and it was the first time I'd heard of it, but it looked good.

I can see the appeal of electric UFH in bathrooms to take the chill of the tiles. I'm planning to have wet UFH upstairs in a concrete screed on hollow core slabs. It'll be heated using the heat from a thermal store (heated via ASHP). With this setup will I be able to lay carpets upstairs or will the heat not be able to get through it?

Thanks @Weegaz

HI @Weegaz, I was reading this thread and just wondering if you decided to go with a lighting designer and if so, what was the outcome?

@Declan52 that sounds like a really good idea - Thanks

I'm in Co. Down and I was wondering... can any of you good folk from NI give me your opinion on whether I should include a roof terrace or not in my build? It's currently included in the house design but I'm toying with the idea of building on up and having it as internal space instead, almost like a 1st floor sun room. The few people I have spoken to say I'm mad having a roof terrace and that whilst the idea is nice, I'll use it very little, if at all. Thanks

Thanks again @MikeSharp01. The Architect offers a service covering RIBA stages 5 & 6 which they refer to as Site Operations & Contract Administration. I assume if the BCO is checking things regularly and I trust the builder, I will not need the Architect to oversee the build. Finally can you recommend any organisations that offer insurance backed warranties?

Thanks @Oz07 - I've a good working relationship with Architect 1 and I know they are swamped with work, so I may try to present it as taking some of the load off him!! You never know, it might work.

Thanks @MikeSharp01. Sorry can you explain what you mean by "BCO scheme" please? Also, if you have any suggestions on how to broach the subject of releasing copyright of the drawings, I'd be interested in hearing them.

Welcome @MrsB

I'm surprised that you guys are discussing/considering/have used electric UFH. I appreciate that it's just to take the chill off the tiles, but surely there's a better way other than Electric?? It seems to fly in the face of low-energy house or Passive House thinking. Signed, Confused from NI

It sounds like you know what you're doing with regards to the drawings & levels. Time spent by you in creating the table will obviously help all the trades involved and hopefully make the build run smoothly. I totally agree, professional chemistry or lack thereof could destroy a project. I know Architect 2 quite well and have been involved in projects with him in the past, so I'm confident that we will work well together.

It's reassuring that it's not just me then. I was under the impression that the Architect was needed to check each stage of the build to certify the end product, almost like a self-builder version of NHBC?

I totally agree. Architect 1, in my opinion had great ideas and Architect 2, has great attention to detail and is very reliable. Any suggestions on how to broach the subject of copyright with Architect 1?