Solar panels on warm roof

[ninro]

We recently had a new warm flat roof constructed.
3 layer felt was laid on top of the insulation/vapor barrier/osb which gives a hard surface but I guess not as hard for taking loads as another layer of ply on top would do.
Could this construction take the load of solar panel racking + ballast without leaving impressions on the roof? (And compromise it) or is 150mm insulation + felt rigid enough?

 

[jj4091]

Ask the installer.

 

[robinbanks]

People walking around on the roof will point load it more than a concrete strip with a solar panel resting on it

 

[ninro]

People walking around on the roof will point load it more than a concrete strip with a solar panel resting on it

Not quite sure what you mean by concrete strip?
The racking systems seem to have a small rubber type pad about 15cm x10 cm that takes the weight of panels, racks and ballast.

 

[StephenStephen]

Would you not use something to spread the load of those little pads?

 

[ninro]

Would you not use something to spread the load of those little pads?

That was my thought however from looking around install on YouTube etc these pads seem pretty standard. Esdec systems have a circular plastic disc as a pad, both seem to have quite a small area to transfer load.

 

[freddiemercurystwin]

Irrespective of the felt and insulation is the flat roof structure up to it?

 

[lostinthelight]

Pv panels work better the cooler they are, would the roof reflect or hold heat...its worth asking the installer I guess.

 

[ninro]

Irrespective of the felt and insulation is the flat roof structure up to it?

When we had the roof built I mentioned to structural engineer that I may want to put solar panels on it in future, pretty sure he factored it in, but It was the builder who didn't put ply on top of insulation which was actually mentioned in original specs. (Though I know this isn't a neccessity).
I'd be pretty sure the structure is fine, it's the surface that's my concern.

I'm aware those tubs need a lot more ballast than 10 degree racking so will avoid them anyway.

 

[freddiemercurystwin]

So what stops the panels blowing away in the wind or are the racks mechanically fixed to the roof (structure)?

 

[ninro]

So what stops the panels blowing away in the wind or are the racks mechanically fixed to the roof (structure)?

Not fixed to roof.. Concrete slabs placed on rails act as ballast. The load can be less as they're angled at about 10 degrees,(tubs are steeper), and a number of panels linked together.