designing a system for a 16th centure timber framed house.

[that bloke.]

hi guys,
i amsoon going to be installing a heating system in an old , thatched cottage. its timber framed with wattle and daub infill's. the eves in the upper rooms go right up to the ridge plate.
there is no ground , wall or roof insulation.

i want an oil fired , pressurised system. i will be using a combi boiler.

now , how do i calculate rad size for a house like this? and , at one point in the future i might want to put underfloor heating in the downstairs rooms so can i use the same boiler when i switch (one by one) the down stairs rads to under floor heating, how can i calculate the size of boiler to compensate for this system change? this may be a year or so after the rads go in but i would rather use the same boiler instead of changing it when the system changes.
any thoughts on this would be great.

[Mike Jackson]

It would help if we knew what angle you are coming from. Are you a householder looking to DIY the job?

You need to search out somewhere that will tell you the U values of your building materials, you can then make an accurate heat loss calculation.

Swapping rads for underfloor is not that straightforward. You can get single room kits but I wouldn't advise a piecemeal approach like this as you'll end up with pumps all over the place. Ideally the UFH needs to be run from a central manifold. I would think about choosing a position for a manifold and running some pipework to it for connection at a later date.

[that bloke.]

cheers Mike. i think the plan now is to fit the combi and just run it for DHW until the UFH is set up and ready to go , is it possible to do this with a combi?

i work as a mate mostly on new builds but ive never done any UFH before so its all new to me. from what i gather its a flow and return from the boilerto a manifold where it gets diverted to pipework under the floor and back to the boiler? i didnt know i needed pumps.
you mentioned a central manifold? i take it this is one large manifold that does all the seperate room systems?

[Bernie2]

Just a quickie!

When you hang the boiler, it usually falls off wattle and daub. Don't forget to fire proof the wall behind it and sleeve the wall the flue goes through. Look up timber framed house installations, there are lots of extras to do.

[that bloke.]

cheers for the heads up Bernie. i am not qualified to install boilers but i will look into it and make sure its done properly.
speaking of quals , can an unqualified person set up the oil tank and oil feed pipes? how much work can an unqualified person actually do to an oil heating system install?

[newbie1]

sounds a lovely house is there not a system that would keep the character seems a shame to have a house of character and wack a combi in
bit like adding upvc windows and coving nice on newer and a shame on older

[that bloke.]

not much i can do about it im afraid , i need hot water and heating.

[david williams]

have you any probs with consevation/listed building people

[that bloke.]

nope , the building isn't listed. its in a conservation area but i think they are only really concerned with the outside. the downside to this is that it has to meet current building regs.
i am thinking , because i have to replace the screed, concrete/latex flooring that i can use expanded clay aggrigate and a limecrete floor with the underfloor heating ontop in lime screed with unsealed pamments on top.
i cant put a dpc down because the house isnt supposed to have one, so the floor will have to be able to let moisture evaporate through it.

i am pretty sure the original floor isnt still down there.

i am trying to work out my btu calculations , i am using online tools to do so but they dont seem to give you the chance to fine tune things, insulation , clay lump/wattle + daub walls , vaulted thatched roofs etc etc.
is there a more accurate way to do this?

[flat pack]

how deep is the sub floor
what about warm air ducting heating / or large air con ducted .
or a arca and a coal fire