How To Box In A Steel Beam

It may have taken us a while, but we’ve finally boxed in the steel beam between our kitchen and dining room.

It’s a job that’s been on our to-do list ever since removing the load-bearing walls between the two rooms but with so many projects around here, boxing in the steel beam never seemed to be much of a priority.

Luckily, covering steel beams with plasterboard turns out to be a very easy project and it’s a project that you can definitely do yourself to save some money on your home renovations. If we’d had known just how easy it was to do, we’d definitely boxed in the RSJ much sooner. 

Although covering a steel beam with plasterboard is easy, it is a project that takes a bit of time to complete. In total, I spent about three full days preparing the beam, covering it with plasterboard and plastering the beam as well as some of the surrounding walls.

The whole room feels completely different now that the steel beam is boxed in, plastered and painted and yet again it’s a project where we can’t help saying “why didn’t we do it much sooner”.

How do you box in a steel beam?

Before you start any work, it’s important to have the structural work like the steal beam signed off before you carry out any work that will hide it. Otherwise, you may have to undo all of the work you’ve already done.

Any structural work has to comply with building regulations no matter where in the world you live and it’s important to get all of the necessary paperwork in order. 

So, how do you cover a steel beam with plasterboard? 

Drilling into structural steel can weaken it so because you can’t screw plasterboard straight onto the steel beam, the first thing you have to do is add lots of noggings that you can then attach the plasterboard to.

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What are noggings and how do you add them to a steal beam?

Noggings are timber pieces that are inserted between the flanges of the steel beams. These timber noggings provide the surface for you to screw the plasterboard to. 

To make the noggins, cut pieces of timer to the size of the distance between the two flanges (the top and bottom parts of the I-beam) with a mitre saw. Make sure that you cut precisely, or a tiny bit larger so that you can firmly wedge the pieces of timber into the steel beam.

What kind of wood should you use for noggins? 

You don’t have to use any special timber to create the noggings. Studwork timber would be perfect but rough-sawn timber battens would be fine, too. Just make sure to use timber that’s chunky to give you enough space to screw the plasterboard to. We recommend using a minimum of 75 x 47mm thick timber.

After adding the noggins between the flanges of the steel beam screw two more timber battens to the top and bottom of each side of the steel beam using the noggings between the flanges to secure them. 

These additional pieces of timber will give you a surface to be able to screw the plasterboard to the underside of the beam.

How do you fix plasterboard to a steel beam?

To attach the plasterboard to the steel beam, cut the plasterboard to the size you need and screw it to the timber battens with some drywall screws.

When boxing in a steel beam it’s important to add two layers of plasterboard to provide adequate fire protection and to comply with building regulations. So, after adding the first layer of plasterboard, add a second layer staggering the joints so that they are in different positions from the joints of the first layer.

Along with hiding the RSJ under the plasterboard, we also added plasterboard to the brick walls around the door and we also decided to temporarily tidy up the wall in the kitchen (it’ll be removed as part of the extension).

After spending almost two days attaching plasterboard to the steel beam and walls it was time to start plastering. Plastering really isn’t one of my favourite home improvement jobs, but it is a great feeling when it is done.

It always feels like a huge jump in progress and everywhere instantly looks more finished after applying a fresh coat of plaster.

When the plaster was dry we could finally get out our paintbrushes. We always use the same method for painting newly plastered walls which works perfectly every time.

Then, just 7 short days (okay, 7 very long and tiring days) later, we finally had our finished dining room!

Plasterboarding A Steel Beam Building Regulations 

Any structural work will have to comply with building regulations and will have to be signed off. A steel beam will have to be protected against fire for a minimum of 30 minutes. 

There are specialist paints you can use to paint a steel beam to give it the necessary fire protection or you can fireproof a steel beam with a minimum of two layers of plasterboard as we did.

Don’t forget to have the plasterboard signed off by building control before you plaster it so that they can see that the work has been carried out correctly.

Although we generally enjoy tackling DIY projects I have to admit that this was a job that I really didn’t like doing. It seemed never-ending, it was messy and the sun was shining which inevitably meant that we would have much rather spent time lounging around in the garden.

I guess not all home improvement projects can be fun and even if we don’t always enjoy them while we’re doing them it’s always a great feeling when we complete them and can stand back and see something that’s not only finished but also something that we achieved ourselves.

What home improvement jobs do you enjoy most? Do you have any DIY jobs that you hate? Have you ever boxed in a steel beam?

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