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External window sill on a 6 panes bay window

My builders removed a wooden 6 panes bay window and very thick hard wood sill to install a upvc bay window.
They installed the bay window but not the external sill. They said they forgot to buy it. I wonder if they can install a sill after they have installed the window or if the window should have sat on the sill at the time of fitting.
I have also noticed that they have filled the space under the bay window poles with foam. They cclearly are not working as bearing elements. Would packing with timber under the poles be sufficient? Thank you

2 Answers from MyBuilder Window & Door Fitters

Best Answer

Hello Vicky, I guess your builders didn't enlarge the width of the opening, so the existing lintels or arches should be able to support the structure above without it bearing on anything below (as it should have done for the windows). Only thing that may have needed consideration if the hole size has been altered in depth - is if the brickwork left is sufficiently strong to properly support under new building regulation requirements - i.e. does it need additional "wind post(s)".
I don't see your builders comments regarding the cill are equitable - "forgot to buy it" is a bit of a lame excuse. There should be a cill at the bottom of a window to shed any water away from brickwork left below and to protect the joint to the brickwork beneath from weather. From what you have said, it sounds that if the window ends with just "posts" the window hasn't a proper cill at all. In most cases this would be considered a manufacturing defect. Certainly on the external side of the building you don't want to be "packing in timber" and to finish with foam beneath the window accept for a thin joint prior to sealing would be unusual. If in doubt, suggest you get someone to view or post photos on the website for comments. Hope you haven't paid the full amount for the job and don't until properly completed.
Eric Marchbanks


Answered 6th Jun 2016

Hi Vicky,

All replacement window & door regulations, for load bearing applications must have adequate vertical bay posts / poles installed where all the frames meet and must have post / pole jacks that screw open to take up any slack.
The weight of what ever is above the bay is spread across of the supporting posts / poles.
You can not should not just fill with expanding foam.

Get there Fensa / certass registration number and report them

regards John


Answered 15th Jun 2016

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