Ensuring old external load bearing wall isn't damaged when inserting beam

I have had plans approved for a ground floor extension and currently in the process of getting building control plans drawn up.

The plan involves creating a 3 metre opening in the external side wall of the semi detached property. It's an old house built around 1935. There is no cavity in the wall just two layers of brick. The foundations are likely to be quite shallow.

My concern is that if we cut open this wall and insert a beam there may well be some movement causing structural damage given the age and condition of the structure.

I was wondering what steps can be taken to reduce the likelyhood of structural damage.

One strategy is to approach someone who can direct the builder as to what steps needs to be taken during this stage of the project. Should I approach a structural engineer or structural surveyor? What is the difference between the two?

A possible solution mentioned to me is laying the horizontal beam on two stone/concrete columns. The portion of ground the columns rest on can be underpinned. This I think would involve digging under the relevant foundation and pouring more concrete.

I would appreciate any help or advice in this.

Thanks

Reply to
Farouq
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This is exactly what my neighbour did, except no special columns were constructed AFAIK -- the beam just sits on the wall, and the underpinning is done at the base of those parts of the wall. That's an 1886 house.

Reply to
Andrew Gabriel

You don't need to worry about this as it is common practice to install a padstone under each end of the beam - a slab of concrete the width of the wall (about 9 or 10 inches in your case) and about 4 inches thick - this spreads the weight of the beam and it's load (the wall above) over a larger area.

That is to say, the weight isn't bearing straight down onto the footing underneath the ends of the beam - it's spread outwards - have a look at this sketch:

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Reply to
Phil L

Thank you for the pic. I feel more reassured now that with the pad stones I can reduce the risk of structural damage.

Reply to
Farouq

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