Best way to vent my roof?

[JamesAsus]

Had a new garage conversion done into a habitable room.

The roof wasn't vented, the roof space above it is only 6 metres squared but NHBC say anything over 3 metres squared needs venting. It's basically rockwoll on top of plasterboard ceiling (no hatch access). It's a lean to roof that abuts against the 2nd storey of my property.

The new window basically covers the full soffit board so I can't fit soffit vents, there is also insulation in the space above the soffit board and i dont think over fascia vents would work as insulation is basically stuffed into the eaves and im not willing to cut plasterboard away to move it all, plus im hoping to do the job myself and think fascia vents look a bit fiddly.

Would a roof tile vent (or 2) be effective enough to prevent condensation issues in the roof void? If I position them close to the top of the roof? Or is it useless without fascia/soffit vents?

Or alternatively would felt lap vents do the job if I put one on each side of the roof at the same level (only if I can access the overlap externally will I consider this, a few rows of tiles aren't nailed down but a few rows are so it depends if I can access without removing nails as I feel that's more tricky than just lifting the unfixed tiles).

The tiles are double roman concrete interlocking.

 

[JohnD]

A lean-to roof?

Is there not a wall at each end?

 

[JamesAsus]

A lean-to roof?

Is there not a wall at each end?

Only on one end, it adjoins another lean to roof section which already has vents BUT there is a breezeblock wall separating that section from this section.

 

[Notch7]

Did you not do a building regs application
Or was it done under a notice

this should’ve been specified before work started

How did the builder know what insulation was required

 

[JohnD]

Only on one end, it adjoins another lean to roof section which already has vents BUT there is a breezeblock wall separating that section from this section.

you could put a couple of well spaced airbricks in. One at each end would have been better.

do you think there is any eaves ventilation?

 

[JamesAsus]

Did you not do a building regs application
Or was it done under a notice

this should’ve been specified before work started

How did the builder know what insulation was required

Yes building regs came round and they were useless and after asking them why ventilation was not discussed or mentioned they tried to pass the book saying it's the builders fault.

The builder discussed with regs what insulation was required.

So back to my actual question?

 

[JamesAsus]

you could put a couple of well spaced airbricks in. One at each end would have been better.

do you think there is any eaves ventilation?

There is no eaves ventilation. Wouldent airbricks be far more work as they would have to cut through 2 layers of brick to fit them, and even then I only have one gable end so there would not be an 'in' and an 'out'???