Bifold door support (moved) needs lintel?

22 Jul 2018
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United Kingdom
I want to change my sliding doors to the garden to bi-folds. I asked an installer who said that although the existing windows were fine, the brickwork above had dropped by about 10 millimetres and he wasn't keen to remove the existing frame to put new bifolds in. There is a concrete lintel above the doorway which has a slight curve on it. Is it possible to put a full metal frame into the space to make sure that my house doesn't fall down if I install the bifold doors. The dimensions are approximately 3m wide by 2.10m high.
Many thanks
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Try asking in the forum marked "Windows and Doors".

This one is called "Forum Information" so not exactly where you need to obtain help from.

Last edited by a moderator:
A steel frame would probably cost more than a new lintel (if needed). Can you post some pics?
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Thanks to Mattylad for help for a newbie

I haven't chosen a door yet, as I wanted to solve the support problem first. I will take some pictures and try to work out how to post them:sleep:

I was looking to change my wooden patio door (linked to conservatory) and all the ones I looked at needed a steel.
I didn't want to go that far
I have just taken these. I am not sure if they are what is needed


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I cant see any dropping or cracks in the pics, Looks like a boot lintel which should be fine.
Maybe get a builder to inspect the lintel rather than a door company. Worst case scenario a structural engineers report or fit a new steel.
An engineers report may not be far off the cost of fitting a steel though.
Thank you. There certainly aren't any cracks in the concrete lintel but it does have a measurable bow. I did ask a builder and he seemed to think it was OK but I thought window experts might be able to speak from experience.
Do you think my existing unit is helping to hold it up and would a reasonably strong framed bifold door continue do the job. Or is the danger that removing the existing unit would weaken the whole structure. I understand that you can't commit yourself but I was hoping that you, or someone else had come across a similar problem before. I don't want to replace the existing lintel as that would be too big a job but I could consider adding a steel underneath it if that is possible. On the other hand, I may have to stick with what I have. Thanks in advance for any responses - I shan't be around for a few hours but I will be back!!

The existing patio door would not be giving any substantial support but may be preventing it bowing a little more. I am no expert on boot lintels but I think they tend to twist a bit in the middle rather than actually bow.
The thing with bi-folds is they have absolutely no tolerance for any downward force from above so thats why your window people are a little worried.
Personally I think it would be fine to do and would leave the door height 15-20mm slack for any future settlement which would be covered by a trim and some foam but I would want someone who knows boot lintels to look at it first and I would probably put a little note on the contract that movement of the lintel wouldn't be covered under the guarantee.

Structurally I would guess that its fine, Its highly unlikely to collapse with no cracks but it only needs to bow the top of the bifold frame down by a few mm to start causing problems with the doors.
Thanks very much. That is exactly the sort of advice I was looking for to help me make a decision.


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