LHall

Thanks @PeterW - very helpful advice! Builder also raised the same issue regarding the weight of the pug mix. I'm think I'm leaning more towards the radiator route and increasing the insulation the floors and walls as much as possible. I'll also look into the heat loss calculation.

Thanks for the advice @markcSpoke with a flooring company who suggested the ply is needed for a more even surface. The 22mm chipboard was what was suggested from the UFH spec diagrams. Would you do something different? Just ply and no chipboard on top of the joists? Thanks for the advice! Thanks @JohnMo for the advice! So just increase insulation to the full 100mm or would you look to somehow put even more in?

Morning all, I'm after some advice as to whether it would be worth putting in a wet UFH system in our 1950s house that we are renovating, and if so, your thoughts about fitting LVT on top. The house has an old garden room extension at the back which we are opening up to make a 5.7x5.6m kitchen-dining area. There will be a vaulted roof over the old garden room which approximately half the kitchen-dining space will be under. We are planning to put some insulation into the old garden room as we don't think it has any at the moment. The house is built on suspended joists with approximately 600-700mm of void space under the original house and 250mm under the garden room. The joists are only 100mm deep, spaced 400-450mm apart. We were thinking of battening from underneath, adding 75mm insulation and finishing with 25mm UFH and dry screed mix. We ideally don't want to raise floor levels due to the lower ceiling height in the original part of the house. Finally, the house faces west and gets quite a lot of sunlight in the afternoon. We are also having 3 velux windows, bifold doors and a window looking out to the garden. 1) UFH vs two big radiators. Which would you get in this scenario for our project? We want the space to feel warm when we need it to but don't know what would be more effective. Would we lose lots of heat under the house? 2) If we were to get UFH then how would you finish the flooring to lay LVT? We were thinking of having 22mm chipboard, then 6mm ply, then LVT. Does that seem about right? 3) We'd like a herringbone LVT pattern but were recommended not to go for larger tiles due to the larger gapping that would occur in sunlight. Does anyone have experience of this? Thanks for your advice, I really appreciate it!