Existing conservatory footings

We have an existing conservatory (brick for the bottom 0.5m) attached to the rear of the house. We are exploring the idea of knocking through and creating a flat roof extension on the footprint of the conservatory. My question is, is it likely the conservatory footings will be suitable for an extension or will they need re-doing? Thank you

Asked by Lee on 27th Sep 2024
Expert Trade Answers
"Hi Lee,

Your best course of action will be to get a structural engineer to visit or contact building control.
If you excavate down the side of the footing before they visit it will give them what they need to answer your question."
Answered on 27th Sep 2024 - Member since Mar 2024 - report
"Hello Lee
My advice would be to excavate to the side of the footing and contact a structural engineer. Dig at least 1 or 2 holes next to the footings. They will then be able to tell you if you have enough footing to take the new weight of the extension. If the footings are a minimum 1m deep, and a minimum 600mm wide you should be ok and not need to redo the footings."
Answered on 27th Sep 2024 - Member since Jun 2024 - report
"the best way to get this answer is to contact building control or building surveyor and they will tell you exactly what you need and guarantee the works if its done correctly"
Answered on 4th Oct 2024 - Member since Sep 2024 - report
"The easiest way to find out is to do a test hole at the side of the conservatory to find out the thickness of the concrete foundation and contact your local building authority to find out the local guidelines and foundation depths for the proposed extension."
Answered on 5th Oct 2024 - Member since Sep 2024 - report
"Hi, you may need to replace the footings, normally you would need a structural engineer’s report to calculate the proposed loads on new structure also to calculate the beam for knocking through from the main building.
Further to this you would need building control to back up and sign off the proposed works.

Hope this helps"
Answered on 1st Oct 2024 - Member since Sep 2024 - report
"Normaly only 500 mm deep most builders do not go down more for a conservatory"
Answered on 27th Sep 2024 - Member since Aug 2024 - report
"Good evening, I believe that the footings will only be 300-500mm deep at present and I think you’ll need at least 1m depth depending on the ground type underneath, ie, clay, sand, stone or earth. A test dig along side the foundations is likely to be need to clear this up for you.
Best regards
Rich"
Answered on 27th Sep 2024 - Member since Jan 2020 - report
"hi ,

Only way of knowing is digging down next to the footing to see how deep they go . Would also need building inspector to check for the sing off at the end ."
Answered on 2nd Oct 2024 - Member since Sep 2024 - report
"It's unlikely in most cases to be honest. You can hope but without seeing photos tough to answer for definite."
Answered on 6th Oct 2024 - Member since Mar 2023 - report
"No the footings will be to shallow as you will need approximately 900mm for a single storey extension"
Answered on 7th Oct 2024 - Member since Jun 2023 - report
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