Porch Roof on Bunglaow with Big Eaves

[FrogParty]

I am hoping to add a pitched roof porch to an uneven U-shape bungalow. My idea is that 3 sides of the porch are formed by the bungalow walls, closing in part of the "U", but not sure how this will work because of the eave overhang of the bungalow roof. A 3D view of the bungalow may help here

The porch roof may be tiled or glass - undecided on that - but shown transparent in the image. The gap of the U is 2.5m wide. It seems it needs box gutters on either side, receiving rain water from both house and porch, but how do I support them? Do I need extra side walls? It is the detailing of how the guttering and eaves will work that is bothering me. Is a porch feasible without major changes to the existing roof?

Anyone done anything like this, or got any suggestions?

 

[noseall]

Anyone done anything like this, or got any suggestions?

Yeah, it's crying out for a flat roof.

If a pitched roof is fitted then it needs to be done expertly with a healthy dollop of care. Otherwise you could be asking for trouble.

 

[Nige F]

Flat roof - absolutely . with a light tunnel in the middle if you really want a bit of extra light

 

[^woody^]

Flat roof with a roof lantern

 

[FrogParty]

Thanks everyone, flat roof does seem to be a consensus. Presumably that is below the eaves level, and sloping very slightly away from the house. I'm not kean on flat roofs but will give it some thought.

 

[noseall]

It can go any position you like, but it will get more complex the higher you lift the deck.

Most sensible (for a porch) would be to say have the roof timbers finish at the fascia bottom, fit the deck, then dress the flat roof material up the fascia and lip under the eaves course of tiles.

However if this was habitable and you wanted the ceilings to line through, then the roof timbers would be at the same height as the house. This would involve removing a couple of courses of tiles and fitting sloping lay boards up the roof etc.

 

[^woody^]

The flat roof joists need to sit on the existing wallplate. It is the same amount of work wherever the roof goes, only it will be and look 100x better

It may look OK with a slim fascia at higher level, otherwise consider a small pitch on the front to keep the facias in line.

 

[hardmetalking]

If you were to use a hard metal material you could have a pitched roof of a flat roof with velux roof lights. Having box gutters either side wouldn't be a problem and they could be in one length avoiding any weak points. The roof would last over 100 years and be maintenance free.

 

[FrogParty]

OK, I have my head around flat roof idea now, thanks.

@Hardmetalking
Steel box gutters were what I was originally thinking about. I have lived with a metal 4m long box gutter on a conservatory for 10 years and it works just great. It is attached along its length to a parapet wall, leaded in etc., and supports the conservatory roof. In the case of the porch the obvious position for the box gutter(s) drainage wise is against the end of the eaves(replacing the ordinary gutter), but I can't see how to attach it adequately. Don't fancy just nailing it to the eaves! Then again if it is made of a nice hard metal material can I just support it either end?

 

[^woody^]

Why would you want the complexity of designing, constructing and maintaining box gutters, plus the cost, plus the compromise on the roof, when there is no need and no advantage?

 

[FrogParty]

Why would you want the complexity of designing, constructing and maintaining box gutters, plus the cost, plus the compromise on the roof, when there is no need and no advantage?

Well drainage could be one reason. It seems to me that a flat roof would receive the rain water from that part of the 3 side rooves, and that does not sound good. Not convinced that box gutters are hard to maintain either, my experience flat roof is more of a maintenance head ache. I would like to have it as an option if I can understand how to support the box gutters.

 

[^woody^]

if I can understand how to support the box gutters.

I rest my case.

BTW, roofs are designed to take any amount of water that goes on them. If you think that three sided recessed gutters and the eaves detail on both sides of them in this situation do not have maintenance issues, then think again

 

[catlad]

Why do you not start your porch roof under you existing roof sofits, and that way you may not need flashings as such.

 

[catlad]

Why do you not start your porch roof under you existing roof sofits, and that way you may not need flashings as such.

 

[^woody^]

There won't be enough room for the joists