Roof for Photovoltaics, Solar Thermal, Rainwater Harvesting, Ventilation and Light Pipes

[SteamyTea]

I was sitting overlooking the sea earlier and for some reason I thought of roofs.

 

Now it is almost certain that most people will have a requirement for at least one of the above, if not all of them.

 

So the question is, do we need to redesign the roof to incorporate all the above in a simple, and ideally, modular fashion that can be adapted to most houses?

 

I find it strange that there are so many different ways of making, what is in essence, a weatherproof covering.

 

So over to the cleaver people on here, and our helpful SE and Architects, @Gus Potter, @ETC, @joe90, @saveasteading and the others who I cannot remember.

All comments/ideals welcome.

[saveasteading]

2 hours ago, SteamyTea said:

ways of making, what is in essence, a weatherproof covering.

Declared  a 'cleaver ' person i should retire now: lay down the sword.

 

So a cleaver statement is called for on that subject. Here goes.

What I used to repeat to keep business relationships in perspective:  None of our clients  wants a building or to pay for it. They just need to keep the weather off their product / staff / family.

 

That doesn't apply to banks, corporations or billionaires as they want to be noticed.. but they were not our clients.

[joe90]

Firstly, thank you for the complement of “clever” (yet to be proven!!!). I think with new builds we are seeing new materials, GRP, metal, composite materials. Historically we have seen materials from thatch, through slate to tiles of differing materials. Mostly roofs are slopes to shed rain, constructed in timber (mostly) with a covering that’s waterproof. So in answer to the question.    

2 hours ago, SteamyTea said:

do we need to redesign the roof to incorporate all the above in a simple, and ideally, modular fashion that can be adapted to most houses?

Why, if what we have works, yes thatch is being replaced (where allowed) with modern materials, asbestos also but change for changes sake is not necessary (I used slate on my build for longevity, proven reliability etc).

[Dave Jones]

if its not broke dont fix it!

 

A pitched roof covered with Stone/slate works is simple to fit and maintain. Also quite like the new recycled slates hard to tell them apart from standard.

 

Just look at USA for cheap, they use shed roofing felt on everything.

 

Can't get too fancy and futuristic or the retarded planning system will enforce against you for 'damaging' a building built when planning permission wasn't required.

 

It would be good to see a system for in roof ASHP, the current box model could be broken up and a solar panel size type heat exchanger for example. 

 

 

[Jilly]

I’m not on your list, but I like what you are implying.

 

I had grand ideals, if not designs, to incorporate these and was disappointed to be thwarted due to the cost of them all. Self building can seem to be endless compromise. 
 

Form and function plus meaningful subsidies? I suspect things could be very simple if cleverly designed, but need to look good (or be hidden) and be ‘affordable’.
 

Experiment with a garden building? There are lots of Heath Robinson low impact ideas which might work at scale. 

[JohnMo]

13 hours ago, SteamyTea said:

do we need to redesign the roof to incorporate all the above in a simple, and ideally, modular fashion that can be adapted to most houses?

Most possibly not. GSE already do (and others) simple trays to displace tiles or slates which will incorporate in to most roofs. PV panels are now so cheap they should be the roof material of choice. You just need inverters that can handle a massive oversized array to the DNO happy.

 

GSE also sell an inlet system for MVHR that draws air from behind PV panels, or outside whichever the most beneficial, getting free preheated air in shoulder seasons and some winter days.

 

If you want solar thermal, you can get solar thermal slates, made from real slate, so invisible on a slate roof. Or combine with PV with integrated thermal PV.

 

Rain water harvesting is a good idea, but you need storage space, which is a stumbling block for a lot of properties, without digging up the whole garden to install.

[Jilly]

There is a company which makes a coffin shaped tank to collect rainwater in the eaves for loo flushing. It wouldn’t work in a bungalow though

[sgt_woulds]

'It wouldn’t work in a bungalow though'

 

Why?  The tank would be above the toilet so can work with gravity feed the same as a 2 storey house.  A bungalow would probably have a larger surface area to gather the water per occupant than a house too.

 

P.s. which company is this?  how do they deal with filtration and maintenance when tucked in a hard-to-reach area?

[saveasteading]

44 minutes ago, sgt_woulds said:

wouldn’t work in a bungalow though'

If it is above the eaves  it won't get water from the gutters.

[sgt_woulds]

Then it wouldn't work in a house either?

[saveasteading]

29 minutes ago, sgt_woulds said:

wouldn't work in a house either?

No. Unless the tank was serving the ground floor only, and positioned in a single storey area or a cupboard.

[SteamyTea]

7 hours ago, saveasteading said:

If it is above the eaves  it won't get water from the gutters

It would if the gutter was partway up the roof, with a secondary gutter to collect the remaining water that falls on the lower section.

 

It is this sort of thing I think roofs need a rethink.

But the general consensus on there seems to be that they are a proven design so there is no improvement to be had.

 

I think differently.

[joe90]

I looked into this years ago and my main worry was storing and moving water above living accommodation rather than just having a waterproof cover. IF I did rainwater harvesting I would use an underground tank filter and pump.

[saveasteading]

12 minutes ago, SteamyTea said:

gutter was partway up the roof

If the gutter happened to be there or conveniently could be designed in, then ok. Maybe. But holes in roofs are to be avoided whatever the purpose. Gutters need overflows too. A usefully big tank also requires stiffening of the structure.

 

So it's not something I would look to do.

I will, however, continue to consider a tank in the ground and a pump. To feed that into the house requires a parallel plumbing system feeding only WCs and outside taps, and a link to mains for when the tank runs out. 

 

[saveasteading]

6 minutes ago, joe90 said:

would use an underground tank filter and pump.

We appear to agree. I did this with a 10m3 tank, this being twice the recommended size. The water bill was tiny as was the related sewage bill. Payback 5 years, which you don't get anywhere else legally. Well, maybe 8 years after costing the plumbing and management critically.

On the latest project I'm thinking of a basic tank in the ground, for gardening only, and a simple pump.

[joe90]

27 minutes ago, saveasteading said:

We appear to agree.

Great minds think alike 😇.   🤣

[ETC]

8 hours ago, saveasteading said:

If it is above the eaves  it won't get water from the gutters.

It doesn’t need to be fed from the gutters - put it on a flat roof and it will fill on its own.

[joe90]

14 minutes ago, ETC said:

It doesn’t need to be fed from the gutters - put it on a flat roof and it will fill on its own.

Eh? Do you mean leave an open tank on the flat roof? What about normal pitched roofs?

[SteamyTea]

56 minutes ago, joe90 said:

What about normal pitched roofs

Would need a lot more thought and detail, but something along this idea.

 

[joe90]

4 minutes ago, SteamyTea said:

something along this idea.

Too much to go wrong IMO and lead to flooding for little gain.

[SteamyTea]

Just now, joe90 said:

Too much to go wrong IMO and lead to flooding for little gain.

Not as if existing roofs never leak.

 

In fact, traditional roofs (UK) are pretty easily damaged, and because they are made from multiple components, hard to repair.

[saveasteading]

1 hour ago, SteamyTea said:

because they are made from multiple components

...the tiles or slates overlap enough that they don't leak immediately.

Primitive and effective.

Modern roofs leak with a single failure.

[saveasteading]

3 hours ago, ETC said:

put it on a flat roof and it will fill on its own.

Under a flat roof is usually a room. Could fill the bath?

[G and J]

I started reading about rain harvesting and two things hit me: even allowing for the sewage % thingy our water bills are so reasonable that payback looks unlikely; secondly the sheer tonnage of plastic involved made me feel that such laudable sounding aims might not turn out to be any kinder to our planet, maybe actually worse. 

[saveasteading]

8 hours ago, G and J said:

maybe actually worse

Agreed. I estimate I've done 300+ projects. Rainwater harvester twice and at least one of these has been turned off. Barrels on rwp, 3 times. Everything on its merits.