Steel posts or masonry pillars?

Industry Professionals - Posted on October 13, 2021

You must often find yourself in a situation where the client wants something ideally, but practically they don’t know what will be involved in achieving it. They nevertheless insist on what it is that they want… FRUSTRATING!! Until, that is… When they receive our structural calculations and the builder is looking to provide them with a quote!! 😊

One such problem which architectural technicians may not sometimes consider, and which has a direct relationship with the client’s requirements and expectations, is to retain masonry piers or pillars, or show a flush finish. So what’s the difference?

The initial (example) problem

A client approaches you and they want a single storey extension at the back of their house, and they want to knock through the rear wall into the extension to create one big room.

Figure 1: Plan showing a typical rear wall of a house with an indicative proposed extension.

But how much should you open up the back wall by? Well, this depends on the client’s priorities for their project.

If cost is NOT going to be a major factor and the client wants a sleek finish…

Figure 2: Plan showing a full width opening with steel columns

Pros

  • Visible intrusion into living space by columns is minimised creating a “single room” effect.
  • Depending on flank wall width and architectural mods (e.g. battening out the wall locally) column can be hidden in the wall entirely if that’s what the client wants.

Cons

  • More steelwork, so more expensive structure.
  • More likely to require work on the foundations, for example new pad foundations, which is more expensive.
  • Steel ground beam may be needed in certain instances where one of the flank walls is a party wall – again, more expensive.
  • Party wall act probably comes into play.
  • Builders don’t like it 🙁

If cost IS going to be a major factor…

Figure 3: Plan showing opening where some of the wall is retained at either support to create piers

Pros

  • Less expensive because usually no re-building of masonry is needed. A steel beam can usually just be installed supported off the existing masonry which is being retained.
  • Usually no work on the foundations is needed because the retained bits of wall spread the load well on the foundations.
  • Party wall act may not be a problem because you don’t need to touch it.
  • Builders like it! 😀

Cons

  • Retained masonry intrudes into the habitable space.
  • Not as pretty to look at.

We hope you have found this article useful! If you have any thoughts, questions or tips you’d like to share we’d love to hear from you. We believe it is invaluable for contractors and consultants to connect and share their perspectives so we can all streamline our workflows and make life easier for us AND our clients. Follow us, drop us a message on instagram and let’s connect @porthousedean_engineers.

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