How to Leave Steel Beams Exposed for a Beautiful Industrial Kitchen

I would say a lot of my interior inspiration comes from the inside of a restaurant or café. We first started renovating when my kids were very young, so I spent a lot of my time meeting friends in coffee shops! I have always loved biophilic and Industrial style décor, I think they sit very well together.

When we started to renovate our kitchen, we knew we had to have very large RSJs (Rolled Steel Joints or steel I beam) put in, so I started to research how to leave steel beams exposed. My mood board for our new home incorporated lots of biophilic designs like exposed brickwork, wooden flooring, lots of light and plants, and having interior steel beams in the kitchen would be the icing on the cake. 

What Are Interior Steel Beams or RSJs?

I think that’s self-explanatory really. Interior steel beams support the building that sits on top of it. They normally have to be added when you take away a supporting wall to extend, put in bifold doors, or knock through rooms.

When we renovated and extended our home, we needed to take out a wall that was over 7m long. Half the wall was an internal wall (and a supporting wall as it was originally an exterior wall before the previous owners added an extra room) and half the wall was an exterior wall.

This meant we needed an extremely large steel beam put across nearly the whole width of our house to support the house above it. As we were taking out a supporting wall on the existing extension and extending lengthways, we also needed interior steel beams to support this part of our house as well. 

I really didn’t want a supporting beam in the kitchen initially, as I thought it would get in the way. Unfortunately, as the interior steel beams would be spanning over 7m, we had to put a supporting beam in to hold the steel up in place.  

You can see the extent of the steel beams needed and the supporting beam in the diagram below. 

As there was no way around having a supporting beam, I decided to make a feature out of it so opted for a round pole. This meant it would be easier to get around and not add extra harsh lines to the kitchen. 

Can RSJs Be Left Exposed?

Yes! As long as you follow the current building regulations, you can leave your steel beams exposed. When I first suggested leaving all the interior steel beams exposed, my builders and husband were quite bemused by the suggestion. They obviously hadn’t been on Instagram as much as me as I knew it would work.

After a bit of persuasion (it was less work for the builders, so they were happy), the steel beams were put in place and ready to go.

How to Leave Steel Beams Exposed

I loved our exposed steel beams in the kitchen instantly. Steel beams are actually a deep red/brown in color, and they provide such an amazing feature. But, do interior steel beams need to be painted? After a bit of research on how to leave steel beams exposed, I realized we would need to put a bit of work into getting them fireproofed. 

Current Building Regulations

If you are going to keep interior steel beams exposed, you have to make sure they are protected against fire if you want building regulation officers to sign off on your build. Interior steel beams have to be protected against fire for at least 30 mins and this is one of the reasons we tend to box RSJs in.

Builders use two or more layers of properly fixed plasterboard around the beams so that the plasterboard will burn first before it affects the beams. You may think, why on earth do steel beams need protection from fire?

The main reason is steel can get extremely hot and start to bend or warp under extreme heat. If these beams are holding up your house, you don’t want them bending as the house will collapse.

Therefore, steel beams need fire protection. If you don’t suitable protect them, your insurance will become invalid and more importantly, it can be dangerous and disastrous!

So, what do we do when we don’t box them in? We use intumescent paint!

Paint for Steel Beams

I have to be honest with you, when I first saw steel beams on Instagram and in coffee shops and other commercial buildings, I thought that the steel came in that color (up until recently, the majority of steel beams I’ve seen are black or very dark grey). I started speaking to Vicky from @house_on_the_crescent and she told me about the intumescent paint and how she’d decided to paint them anthracite grey.

I absolutely loved the result of her exposed steel beams in the kitchen and knew I wanted ours to be the same.

What is intumescent paint? It is a thick coat of paint that reacts to heat by swelling to several times its thickness, creating small bubbles which act as an insulating layer. This creates a barrier that protects the steel beams for up to 120 minutes longer than if they’d been painted with normal paint.

The paint can be quite expensive and hiring someone to do it for you, is even more so. I would say it is definitely a DIY job! The paint itself is extremely thick and tar-like in texture, so it can be tricky to apply and arduous on your arms and wrists!

How Much Paint Will You Need?

I bought Thermoguard Thermocoat WI which is a low-odour, water-based coating from Rawlins. How much paint you need depends on the paint brand, how much space you need to cover, and how long you want the fire protection for.

As our steel beams measured 15m in total (including the supporting beam), I bought 2 x 5kg of Thermocoat WI. There is a handy guide to what you’ll need on the Thermoguard website.

How to Paint Steel Beams

As I said before, the paint is extremely thick and tar-like. You can apply it with a brush, roller or an airless sprayer (although, as it is so thick, this can be more work than painting with a brush). I decided to go with the small sponge roller option with a small paintbrush to get into the corners and around the bolts.

Here are my top tips for painting interior steel beams –

1. You need to give the paint a good stir before applying it as it is so thick. This helps to stop it from forming clumps or bumps and leaves a smoother finish.
2. Use a paint roller. You can apply the paint with a brush, roller or airless sprayer but I found the paint roller to be best when it came to application. The brush left visible strokes and as the paint is so thick, it kept clogging up my paint sprayer.
3. If you use a roller, make sure it is a foam roller. A short pile or long-haired roller sleeve did not leave a smooth finish and if you take a break (which you will need to!) the paint would clump around the pile.
4. You will need to do at least 2 or 3 coats when using a roller as it goes on quite thinly. I did 3 coats on our steel beams. I left at least 2 hours between each application. Mainly because it took me around 2 hours to complete one steel beam before I could go on to the next one.
5. Leaving the paint to dry between applications makes sure it remains bump-free and smooth
6. If your paint is a little bumpy or you’ve painted areas you shouldn’t have, leave it to dry and then you can sand back a little and repaint. I wasn’t too worried about the strokes or bumps, I like imperfections in my home as it helps the features to feel like they’ve always been there!

The paint is extremely thick, so always give it a good stir before you pour it into a tray. I (slowly) poured it and used the sponge roller to paint a thin layer over the steel beams. I applied 3 coats and it took me around 3 days to complete. However, as a rule, it is probably best to keep applying layers until you have used all the paint. 

The Topcoat

You definitely will not want to leave your steel beams the color of the intumescent paint (white) so you will need to apply a topcoat and color over the intumescent paint once it is completely dry. I struggled to find a definite answer as to what kind of paint you should use over the top.

It is the intumescent paint that does the job of protecting the steel beams from fire, so surely you can use any type of colored paint?

However, as this needs to be signed off by building regulations, I decided to play it safe and ordered a pot of topcoat paint from Thermo Guard. They can do you any color if you have the RAL no. and, as I wanted the steel beams to be anthracite grey like our bifold doors, we ordered 2.5L of Thermoguard flame retardant topcoat in RAL 7016.

I do think this paint is extremely overpriced though, as you are basically buying eggshell paint. If I was to do it again, I would have bought normal paint for the topcoat.

You’ve Painted the Beams, Now What?

You need to get the RSJs signed off by building control! Depending on what paint you use, you can get a certificate from the paint company to say you have applied it, but at a cost!

A bit like the topcoat paint, I don’t think it is necessary to do this, and is just another silly expense. How does the paint company know if you applied what you have said and done it to their specifications?

Prior to leaving our RSJs exposed, we phoned our local council building regulation officer, and he explained what we needed to do. He was happy for us to apply intumescent paint and when he came around to sign off the building work, we showed him the (almost empty) paint can and some photos of us applying it and he was happy with that.

I don’t think you need to pay for a certificate from a paint company. The best advice I can give is to ask the building regulations officer first, they are the guys who will sign off on your steel job!

And that’s all there is to it. I absolutely love our exposed steel beams in the kitchen; they add a bit of character to our kitchen that initially lacked features.

We get so many positive comments about them and a lot of people say they would never have thought to have exposed beams in their home. They really add to the industrial and biophilic feel of the room and I would recommend leaving exposed steel beams in the kitchen to anyone! 

Now all you need to do is decorate the room with some Smart Industrial Designs

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