Replacing 7 facet Bay window

[frank999]

Hi I have two large old wooden 7 facet bay windows to replace - with uPVC.

This is my first bay install, more complicated than it seems.

The upstairs window has a tiled gable on top - with brick under its eaves, so assume a load is being carried, and the ground floor window supporting this weight + a rendered wall above.
I will be using Bay Window Jacks, (am unsure whether to use 1.8 or 2.74 Ali. tube at this stage, guess its doesn't hurt to over spec.)

Read this thread which was quite helpful:
//www.diynot.com/diy/threads/bay-window-problems-advice-needed.328717/

I read that proper supports 'would probably consist of a steel angle supported on corner tubes, and tied back to the main wall of the house each side of the bay.' would this be a one piece steel angle, cant see how you'd thread a 3mt peice through with Acro's in place ?

Would I be right in thinking that the ceiling joists in the roof rest directly on the top of the existing upstairs wooden frame, and same for the ground floors ceiling joists.

Once the old frame is removed - there will be no direct support for these joists, would additional noggins/blocking between existing joists, acting as a sort of trimmer between the joists be man enough to carry the weight from the joist to the bays jacks - which in some places would sit mid span on the noggin ? are they suggesting steel angle placed - under noggins ??



View media item 93549

 

[Gazman16]

Some photos might help but generally there is no way to tell exactly how its built until you take the window out.
In theory the structure should mainly be bearing down on the existing corners but you never know. Noggins themselves would probably not be man enough but combined with spreader plates should be fine.
These guys are good if you are unsure on anything http://www.windowwidgets.co.uk/technical/baypole-jacks-compliance/

 

[frank999]

Hi,
Thanks for the reply, yes I came across windows and widgets - very helpful, I have looked at other windows in the street, and have a cross section of one of these windows - the top header of the window is timber 95x45mm, so if I remove the window, and where this header sat, fit C24 timbers of the same size and position to the old frame, as long as bay poles press against part of this new timber that is near to joists above the weight should be spread - I will tie the 'join' above with additional timber and fixing to the joists, I will go up and take some more measurements - spreader plates may be required where the facets meet at points midway between joists. Yes point taken on weight bearing down on corners !

Have posted another question about the Bay Poles Load bearing capacity, pic of the property is there:
//www.diynot.com/diy/threads/bay-window-pole-supports.445351/

 

[crank39]

How not to install a bay, a job I was called to to survey for the reason the barrel had dropped, removed the fascia trim to reveal this

 

[frank999]

Wow that is ... s**t.

So the fitters have gone to all the expense of rocking up with a new set of windows, removed the old, kept the rotten old headers and completely ignored any requirement for load bearing.

If you keep the old headers (which are part of the frame) - can I assume a spreader plate at the angled join of each header, will spread the load down to where the top of the bay pole jack presses ?

 

[crank39]

The old window headers were removed, what we found was the old timber lintel probably an 8x4 lay on its side had rotted out or at least the forward 4 inch of it so the installers hacked away at it to remove the rot and nailed some timber they found by the looks of it to the remaining timber lintel. You might think that's OK but what you have left is a lintel who's ends aren't supported and because its now only half the width it has fell in behind the window frame and is being pushed through the lounge ceiling, the lintel is 8 or 9 inches wide because it supports the internal skin of the barrel, normally these are single skin stud work with bricks laid in between but this one has a cavity and full width window boards inside, what we have now is the internal skin resting down on the rotten lintel which in turn has fell inside the downstairs bay and is coming through the ceiling.



The outer barrel is coming away from the house and was close to falling into the front garden, left 3 acros on site with 4 x 2 holding the barrel up and had to ratchet strap it back to the house to be safe

 

[Gazman16]

Im guessing the window company have done a runner then and this is an insurance job?

 

[frank999]

Wow even s***er, people have been killed by falling bays ! very dangerous.

Thanks for sharing, its laughable to see where they have used packers (obviously funny not, for the poor householder).

 

[crank39]

Im guessing the window company have done a runner then and this is an insurance job?

You got it, that's all we do!

 

[Gazman16]

I do moan a bit about the cost of the insurance sometimes but then you see something like this
A £40-50 insurance policy and they will probably have to pay out thousands on something like this, It is a good thing FENSA are forcing company's to issue insurance really.
I just hope that company haven't done alot of bays.

 

[frank999]

Attached is a CAD image looking down on the Bay Canopy structure, which supports a tiled roof, the outer most facets have a 120 degree angle with the return facet - what sort of spreader plate would you use under the retained headers, Window Widgets referred me to Duraflex (whose windows these will be) they can sell me a 3mm thick, 120-150 degree stainless steel spreader - would you be happy with just that or would you suggest something more elaborate, I am concerned the bearing wont be sufficient.

 

[frank999]

Here is a CAD of the shim plate, is 3mm thick enough to bridge the gap between headers ?

 

[crank39]

I do moan a bit about the cost of the insurance sometimes but then you see something like this
A £40-50 insurance policy and they will probably have to pay out thousands on something like this, It is a good thing FENSA are forcing company's to issue insurance really.
I just hope that company haven't done alot of bays.

The policies cost about £15 which is stupidly cheap for a one off payment for 10years cover. Over and over again the customers tell us the installer has set up again with a slightly different name but same premises same vans same people, I think its about time fensa and certass somehow weeded these types out and refuse membership OR crack down on inspections maybe inspecting every other job