Patio over aluminimum door sill

[James Carmichael]

20210728_122630

• James Carmichael
• 28 Jul 2021

Hi,

We had bifold doors installed about two years ago. Outside there's around a 40cm drop to the garden and the plan at the time was to run steps down, so the installers included a 225mm aluminium sill. The doors are face drained and sitting on a slate undersill, so the aluminium sill isn't serving a whole lot of practical purpose.

Plans have changed and we now want to raise the patio up to do the 'on trend' continuous floor level between inside and outside thing, with outside being 900x600 Indian sandstone slabs (nominal 25mm thickness) - so the first row of slabs will protrude 900mm out from the doors.

The window installers have told me that I cannot remove the sill without demounting the doors, bad as it is all now decorated and sealed in. They also advise against cutting the sill.

I assume I can't simply cantilever the slabs over the sill (so, leaving the ~250mm nearest the house unsupported)? They'll only be taking foot traffic but I wouldn't be popular if some landed heavily on the end of one of them and bounced it up. Similarly, I assume I cannot use the aluminium sill to support the slabs (it's a box profile, but doesn't have the look of something strong).

What do people do in this sort of situation? Whatever we end up doing, it'll still need to allow water run off from the doors. My best guess is to ask someone smart to design some steel brackets that can fit under the sill and present a steel bar/plate above it that the slabs sit on.

Or, is all this just overkill and the slabs will be just fine cantilevered with the 650mm or so that is mortared down more than ample to stop them kicking up?

Thanks

James

 

[JohnD]

Plans have changed and we now want to raise the patio up to do the 'on trend' continuous floor level between inside and outside thing,

Oh great. You want to cause damp in your house by raising the ground level and bridging the DPC.

You will find plenty of threads by people with this problem, and the trouble and expense they suffer.

 

[James Carmichael]

Oh great. You want to cause damp in your house by raising the ground level and bridging the DPC.

You will find plenty of threads by people with this problem, and the trouble and expense they suffer.

They may well do, but (a) We are not planning to attach the patio to the building (b) the steps that were removed were attached to the building and had been there for 110 years, were only 5 cm lower than our proposed not-attached patio and (c) Our house does not have a damp proof course in that location, and never did. Before you tell me it does, do not waste your time or mine. It does not. I know this to be true.

Back to the topic in hand - do you know the answer to the question asked, or are you just the make-snide-remarks-from-the-sidelines type?

 

[davestripe]

Hi James, did you ever find a solution to your issue? I have exactly the same and still wondering how to solve it!