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Hi all,
Seems this sort of thing comes up pretty frequently here but would really appreciate some input/help.
Long story short, we're building a small single-storey flat roof extension at the back of our bungalow (plus full reno and some internal reconfiguration). It joins an existing flat roof extension (historic) on one side and the garage wall on the other. During the process our builder found that the deck in the existing flat roof was wet, and advised we should do the whole roof. The whole thing is now continuous GRP.
Building control have now said, on the basis that we've done the whole flat roof I think, that we need to upgrade the thermal efficiency and cross ventilate through to the front of the property which is going to be a massive undertaking according to builder and frankly we can't afford it. Apparently the main pitched roof doesn't have a breathable membrane which also matters?
Having done a lot of reading in the last few days I realise now we probably should have taken the opportunity to convert to a warm roof but you don't know what you don't know.
Given that we're not going to remove the GRP roof now I guess I'm looking for alternative ventilation solutions to a) prevent condensation as much as possible and b) satisfy building control.
I've seen that there are products for venting along a join between flat roof / wall (abutment vent), is there anything similar for flat roof to pitched roof? Any and all help much appreciated as this is holding up the rest of the build and I'm worried we're going to get completely stuck.
Some additional info:
- Extension falls under permitted development, relevant submission made.
- Building notice was submitted with some basic plans from a family friend so no architect on board (yes I know). I'm not sure whether the builder had any idea about ventilating the new flat roof.
- The whole flat roof section will cover an open plan dining room and kitchen, then an internal wall and bedroom. So high use.
- Joists run from back to front of the property. Considered ventilating along the width of the flat roof through the garage but not sure would be enough air flow.
- There's no insulation up at the moment and the GRP hasn't been joined to the pitched roof yet.
Seems this sort of thing comes up pretty frequently here but would really appreciate some input/help.
Long story short, we're building a small single-storey flat roof extension at the back of our bungalow (plus full reno and some internal reconfiguration). It joins an existing flat roof extension (historic) on one side and the garage wall on the other. During the process our builder found that the deck in the existing flat roof was wet, and advised we should do the whole roof. The whole thing is now continuous GRP.
Building control have now said, on the basis that we've done the whole flat roof I think, that we need to upgrade the thermal efficiency and cross ventilate through to the front of the property which is going to be a massive undertaking according to builder and frankly we can't afford it. Apparently the main pitched roof doesn't have a breathable membrane which also matters?
Having done a lot of reading in the last few days I realise now we probably should have taken the opportunity to convert to a warm roof but you don't know what you don't know.
Given that we're not going to remove the GRP roof now I guess I'm looking for alternative ventilation solutions to a) prevent condensation as much as possible and b) satisfy building control.
I've seen that there are products for venting along a join between flat roof / wall (abutment vent), is there anything similar for flat roof to pitched roof? Any and all help much appreciated as this is holding up the rest of the build and I'm worried we're going to get completely stuck.
Some additional info:
- Extension falls under permitted development, relevant submission made.
- Building notice was submitted with some basic plans from a family friend so no architect on board (yes I know). I'm not sure whether the builder had any idea about ventilating the new flat roof.
- The whole flat roof section will cover an open plan dining room and kitchen, then an internal wall and bedroom. So high use.
- Joists run from back to front of the property. Considered ventilating along the width of the flat roof through the garage but not sure would be enough air flow.
- There's no insulation up at the moment and the GRP hasn't been joined to the pitched roof yet.
