Planning an orangery extension to our house. Originally thought, underfloor heating and radiator to keep it warm.. But now not sure as I have been reading things. Firstly, can I add a radiator as an extension of the house heating? (Combi Gas boiler) Can I add underfloor run as extensoin of house heating? Thanks
Assuming your boiler can handle the additional load, you can extend the system into an orangery.
If you want the orangery as a separate room, then you may be able to build it without building regs, but it will need to be thermally separate with external quality doors. Its best to check with the LABC, I write them an email: 'please can you confirm this orangery, which is less than 30 sq Metres, is substantially glazed and thermally separate from the house is an exempt structure.
If you extend the CH system, then you need separate controls, IE TRVs on any rads. I was told by a private inspector, this wasnt acceptable, however I managed to find a building control guidance note that stated TRVs are accepted.
If you are having a permanent opening, you dont need separate controls, although you might as well. You will then need building regs. And a SAPs test will be needed.
Unless you are on a tight budget, I would suggest having building regs anyway. That will mean foundations, floor, roof will be inspected by somebody independant from your builder. In any case, make sure the orangery has structural calculations for roof loading and lateral stability.
Bear in mind building regs gives you sone piece of mind, but may cost you more if a pedantic BC requires deep footings etc.
Wet underfloor heating, in screed system and an extra rad, is the best possible heating for an orangery. Put the pipes on the insulation, screed over. Have expansion foam around edges.
Ive built orangeries with underfloor wet systems and done correctly, they are really toasty warm. The heat is down by the floor, where you want it, whereas just rads will convect the air which will rise and get trapped high up under the lantern.
One rad as well is ideal for those unexpected cold mornings when the floor hasnt been on.
You can run underfloor heating from the boiler, but you cant just extend house system. Extending from rads nearby wont work, you need a flow and return plux control wires going back to boiler. Extending rad pipes is very limited as orangery u/floor can only be on when house system calls for heat -Im sure there are plumbers on here who understandvthat much better than me.