Overal building is about show box proportions, with a simple duo-pitch roof with exposed trusses for about 75% of the area ie in x section a rectangle with a triangle on top... but with a 'mezzanine pod' sort of thing over about 25%.

Any idea how (/if) I take account of this in SAP, for some back of beermat Code calculations...?

J

The above details a mezzanine in a chapel conversion. The ground floor is the area-weighted average storey height of the area under the mezzanine, and the full height 'gallery' area.

Cheers...

...on a similar theme, (well not really but same project...) I am looking at some very large areas of glazing (triple) facing an unheated space which then has some very large areas of (double) glazing separating it from the outside, (kind of like a conservatory but in a sort of tasty-architectural-attached-sun-space kind of way rather than an 'Cold Seal Conservatories' kind of way...).

Now SAP says:
"For a conservatory which is thermally separated, the calculation should be undertaken as if it were not present."

but

"Stairwells and access corridors are not regarded as parts of the dwelling. If they are heated they are not
included in the calculation. If unheated, the U-value of walls between the dwelling and the unheated space
should be modified using the following data for Ru...."

So it seems to me that the 'tasty-architectural-attached-sun-space', neither contributes to the SAP calc in terms of conditioned floor area (ok I'll buy that), but that it also has no effect on the heatloss of the wall / glazing it covers... seems a bit duff to me, would of thought it was at least the same as a quad/quintuple glazed window...?

...or as is more likley I've missed something...

J

...how reasonable do you think it would to treat the conservatory as part of the wall build up for U value purposes. Ie quintuple glazing where you can stand in the penultimate cavity...?

J

Posted By: James Nortonhow reasonable do you think it would to treat the conservatory as part of the wall build up for U value purposes.

The conservatory is a ventilated cavity, so I think you should disregard everything outside the cavity (i.e. the conservatory walls and roof)....

Alternately, the walls and roof of the conservatory are likely to have a much greater surface area than the wall of the building that they share, so their effect on the U-value will be minimal and you're probably safe to ignore it....

OTOH, the temperature inside the conservatory is probably a few degrees warmer than that outside, and the inside of the conservatory is not in 'exposed' conditions, so clearly the actual heat loss will be reduced a bit. Perhaps best kept as insurance so that actual heat loss stands more chance of matching designed heat loss?

I would go with 100%

They could have used the word 'sealed' instead.

Many thanks!