Heat loss calcs on thatched roof

[sjmac]

I am trying to work out heat loss calcs on a thatched property. There is no access to the roofspace, so the insulation if any is unknown. If you do the calcs as a standard felt & concrete tile with no Fiberglass the losses are massive. The thatch would be providing insulation and creating a "warm roof" not to dissimilar to some new builds that we do. No ceiling fiberglass with Celtex fixed to the rafters then batten and tile. I'm trying to find a middle ground. Obviously too hot is better than too cold, but don't want to cook the upper rooms.

Any advice/thoughts ?

Scott

 

[Agile]

You say no access to roof space!

Is there a loft with a flat area above the ceiling?

If so my advice would be to create a loft hatch and add insulation.

Otherwise aim for combating a massive heat loss!

Tony

 

[Biggles..]

Thatch roofing systems are high for insulation value. Going up and craning insulation in may well not actually benefit how a thatch roof functions.

Middle ground will see you right.
100w sq m will be more than adequate

 

[sjmac]

Thanks Lee. Tony, this was my point you can create a "warm roof" as in loads of new builds I see. At the end of the day if the fabric is upto temp, then all is good. You only have to look at the rad sizes in new properties, mentally small. 3 bed new build 3 x 450 x 600 singles plus 450 x 400 on landing then only a few 450 x 800 doubles downstairs. My Dad can't believe it, poor old Cxxnt was dragging a 600x 1000 k2 into the house, before checking. Obviously my dad was the bloke who hung a Neateat 16/22 with one hand while shimmy the cast iron bath with the other. Proper, that was. Chiropractors wet dream...

 

[45yearsagasman]

I could offer some advice, but I'd only be grasping at straw............I'll get me coat.

 

[Agile]

We dont know the size of loft space.

Whilst the thatch itself has a good insulation value there may be a large loft area which without insulation would need heating up and extend warm up.

I would be inclined to still add some insulation if the loft area is large. But probably only say 75mm and primarily to increase heat up time for the room below.

But nothing has been said about the walls or the floor. Most thatched properties have thick solid walls and solid uninsulated stone floors. That can be fine when up to temperature but needs more heat input when heating from cold. I would be thinking of 150w/psm

Tony