Knock through, RSJ, End bearing and SE

Not open for further replies.
27 Jun 2017
Reaction score
United Kingdom
Please do not duplicate your posts

This is my first post, for a while I have enjoyed reading through many posts and learning :).

I have a 3 bedroom end terrace (ground floor and first floor with truss roof), i have had an extension built to the rear of the house via permitted development (external size 3mx7m with vaulted roof). I now want to knock through the back of the house which is a cavity wall (260mm). The opening will be around 6.5m which i know is a large opening.

I have followed all building regulations regarding the build work and have been advised that i require steel calculations for the opening along with padstone spec and end bearing size/length from a structural engineer, which of course i am happy with.

The SE first stated that due to the opening size i may require steel posts on the sides of the opening, i believe he may of changed his mind now (yes not great). Now he is suggesting that the end bearing walls may need to be 600mm each which is not want i want for a open plan space. i have told him that 600mm is too big for end bearing but he is suggesting that I need to pay his quote so he can conduct the calculation to truly determine how much of the wall i need to leave.

I do not have plans as the build work was done on a building notice, however i have attached some pictures and the SE has modified my estate agent plan.

Sorry for the long post, would just like some guidance.

Thank you


  • Plan - Layout.pdf
    678.3 KB · Views: 253
  • Loft 1.jpg
    1.4 MB · Views: 246
  • Loft 2.jpg
    1.2 MB · Views: 227
  • Wall to knock out 1.jpg
    Wall to knock out 1.jpg
    122.1 KB · Views: 263
  • Wall to knock out 2.jpg
    Wall to knock out 2.jpg
    120.5 KB · Views: 250
  • Wall to knock out 3.jpg
    Wall to knock out 3.jpg
    106.3 KB · Views: 291
  • Rear of house.jpg
    Rear of house.jpg
    223.8 KB · Views: 256
Sponsored Links
Sorry for the double post.

I am happy to change SE if anyone believes that may help, i am in the Leicestershire.

thank you
Yes, which I thought was normal.

I do not want to pay the money and the have the SE say that I need 600mm end bearers. I am no expert at all but 600mm seems incredibly large.
Sponsored Links
It's not normal where I come from but maybe he does that on domestic jobs to avoid chasing clients for payment.

In a roundabout way though you seem to be suggesting that if he can't design out the piers you won't pay him. Anyway better off posting in the Building section, I would hazard most engineers would have a pretty good idea before they did any calcs.
Payment is not the issue.

I rather not waste his time and effort if he believes I need such a large end bearing. I will then have to explore other avenues to use the space.

Thanks I will post in the building section.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Not open for further replies.