Conservatory - will foundations support glass roof?

AmmDram

Just looking for a bit of help please regarding our conservatory, before I try to get quotes, as it seems to be very hard at the moment to get people out to quote for anything so I want to be sure of what we need…

The house currently has a conservatory with dwarf walls to two sides and full brick wall to the other short side. Internally it measure 5m x 1.7m. It has a polycarbonate roof which we are looking to replace. I’d like to replace it with glass but not sure if the foundations will support a glass roof? 

I have the following information from when it was built back in 1982… if anyone can tell me if this is likely to be able to support a glass roof then I’d be very grateful. Thanks. 

AmmDram

Well, it only really has a dwarf wall to the main glass side (the 5m wall) as the other short side that isn’t completely brick looks like this…

WaywardDriver

No mention of Building Control approval. When we replaced roof with lightweight tiles, BC insisted on a load test. May be different with your local BC so best to ask.

weeg

It totally depends on the ground under your house, but those footings are pretty standard for a 2 storey timber frame house, on reasonable ground, so should be fine. If both side walls are brick, then a standard roof should be fine. 

Jeepers_Creepers

Will the founds support it? Of course it bleedin' will. Unless you are currently limiting occupants of that room to a max of two at a time? Have the founds sunk under the weight of the dwarf wall? The large DG units? No? Well it also won't do so by adding a few sheets of glass. There's yer SE calculations done.

More important, tho', is - will the windows/frames support the new glass roof? What's at the opposite end to that full wall, AD? What's supporting these joists at their other end?

greenface2

the person above makes sense . thanks jeepers . regardless what is at the other end . There should be something . But if there is nothing you could add a support end to end to put your glazing bars onto it .If you're thinking of a bifold as everyone is at present you will need to think about the support of that and maybe need to construct a steel "goalpost" style depending on what your walls are made from ,  . I would only advise going inside laminate (min 6,4 ) and toughened active blue would be my option . Its thermal values are better and also self cleaning .

fezster

600mm foundations should be more than adequate for a glass roof. The problem you will have is proving it to Building Control - unless you had BC approval in 1982, you may be required to make inspection holes. The frame of the conservatory will also need to be modified to support the additional load.

Sorry Jeepers, I disagree. The weight applied on the slab of the conservatory has very little to do with the load applied on the walls / existing structure. You could park a truck inside the conservatory (if it will fit!), that doesnt mean the foundations are adequate to support the weight of that truck.

Jeepers_Creepers

fezster said:

Sorry Jeepers, I disagree. The weight applied on the slab of the conservatory has very little to do with the load applied on the walls / existing structure. You could park a truck inside the conservatory (if it will fit!), that doesnt mean the foundations are adequate to support the weight of that truck.

Totally get what you are saying Fez, and technically you are - of course - correct.

In practice, the slab will be far less capable of carrying loads than the walls - the amount of hardcore and packing and concrete slabbing for the floor tends to be a lot less than that of the founds - so if you could park a truck on the slab without issue, then you could park a tank on the wall.

I know it's wrong to suggest this, but I know what I would do. I mean, would I entertain relaying or underpinning the founds for a connie? Lawdie no! I would go ahead and fit DG roof units in the sure knowledge that if the current setup has worked for X years without a sinking feeling, then adding a couple of hundred more kilos spread out over the whole caboodle ain't going to make any more difference. At least not to the founds. And it's the founds we are talking about.

Two guys come staggering in carrying a large DG unit between them. "Just set it down over there - rest the edge on the window cill. Lawdie! The dwarf wall is sinking!"

Nah

greenface2

total weight for my spec 6.4mm lami / 4mm toughened active blue would be around 220kg ( about 35 stone) its not ground breaking . it really isn't ground breaking . If split into 5 that's 7 stone per pane  over a 5m span 

AmmDram

fezster said:

600mm foundations should be more than adequate for a glass roof. The problem you will have is proving it to Building Control - unless you had BC approval in 1982, you may be required to make inspection holes. The frame of the conservatory will also need to be modified to support the additional load.

Thanks for replying. We only just bought the house; the owners before the previous owners had the conservatory built. I was hoping the plans would have enough info. Do I need to speak to BC before getting someone out to quote? Is adequate framework something the conservatory companies/window fitters should take into account? I have no idea and don’t want to end up with it done incorrectly/dangerously… 

AmmDram

greenface2 said:

the person above makes sense . thanks jeepers . regardless what is at the other end . There should be something . But if there is nothing you could add a support end to end to put your glazing bars onto it .If you're thinking of a bifold as everyone is at present you will need to think about the support of that and maybe need to construct a steel "goalpost" style depending on what your walls are made from ,  . I would only advise going inside laminate (min 6,4 ) and toughened active blue would be my option . Its thermal values are better and also self cleaning .

Thanks. We can’t put bifolds in as the garden level outside is higher up than floor level inside (if that makes sense?). 

We would like to replace the windows at the same time as doing the roof, so basically everything except the brickwork….!

We would like to put some large windows in at the front which will open adequately to let a lot of air through to make it more usable (currently only the tiny windows open), and replace the old polycarbonate roof with the most appropriate glass for the job. Am worried about getting it wrong or employing someone to do it and it being the incorrect way to go about things.