Subscribe to our Mailing List

Get the news right in your inbox!

Privacy Policy
How to Expose a Steel Beam

DIY: Exposing a Steel Beam & Fire Protection

November 10, 2016 - 22 Comments - 8 min read

Steel beams – you either love them or hate them. Their purpose has absolutely nothing to do with being an interior statement, but to safely support the building that sits on top of it. However with industrial interiors becoming a growing trend, there’s nothing that quite punches a statement of industrialism more than an exposed steel beam. But keeping a steel beam as a feature to a room isn’t quite as simple as it sounds. Nope, there’s building regulations to adhere to and safety aspects to consider first.

Current building regulations (October 2016) state that steel beams must be protected against fire. Whilst steel obviously isn’t going to set alight and burn to the ground – it can get very very very hot and bend or warp under extreme heat. If this steel is holding your house up – well, it wont be holding it up for much longer if this were to happen. For this reason, steel beams are covered in either two layers of plasterboard of one single layer or fire-rated plasterboard. Both of these give fire protection to a steel beam for so many minutes (usually 90!).
You can’t simply keep a steel beam exposed as there’s no protection for it against fire – which would firstly invalidate your home insurance as it doesn’t adhere to current building regs. But even worse, it could cause considerable side effects if a fire were to ever break out. Therefore to expose a steel beam, it must still be fire protected in some way.
exposing a steel beam
If you’ve been following our kitchen renovations, you’ll know we had a pretty chunky steel beam installed when we knocked through the kitchen and dining room. We were keen (or I should say, Grant was keen!) to keep this exposed. After all, it’s not every day you get the opportunity to show off an industrial sized steel beam within your home! I have to be honest though – it wasn’t the look I was really going for when I had first envisioned this room, but the idea grew on me over time and I decided to give it go. If I absolutely hate it – well, I can always cover it up right?
So I did heaps on research on this topic and thought I’d share how to expose a steel beam properly and safely if this is something you’re considering too. So here’s a quick snap of our steel beam – it’s a UC twin steel which means there’s two of them bolted together either side.

steel beam in kitchen renovation

Intumescent Paint

How does one fire proof a steel beam without plasterboard? The answer is intumescent paint! It’s a paint that basically swells up during excessive heat and protects whatever’s underneath. There are a few companies out there who will paint and protect a steel beam for you, but the cost of that I’m sure is far more than I was ever willing to spend. For DIYers, there are a few companies that sell intumescent paint, but it’s still by no means a cheap product to buy. Particularly compared to fitting a piece of fire-rated plasterboard which would have been less than £10!

The paint we’re using is by a brand called Zero Flame which we purchased from Rawlins Paints.

intumescent paint for steel

How Much Paint Do you Need to Use?

This depends on the brand of paint, the total amount of surface area you’re painting, the type of steel beam, how many sides will be exposed and how many minutes of fire protection you need. Yes, it sounds so very complex and I’m not going to lie – figuring this part out wasn’t exactly the easiest. There’s a very simple chart on the back of the tin that translates this much simpler and easier, but it still wasn’t very fool-proof in my opinion. If you’re unsure, please ask your local building control.

So in our case, we’re exposing 3 sides, it’s a horizontal beam and has surface area of 2.2m squared. According to the chart we needed to buy a tub of 2.5l and use just over 2/3 of the tub. Yep, it’s really that non-exact in calculations.

how to use intumescent paint

How to Apply?

The paint I’m using claimed to be suitable for brush application, roller application or spray application. I thought using a brush would be the easiest with the inner corners on each side, going around the bolts and with it generally being a bit of a tight space. It turned out however, that using a brush was a big mistake.

This paint is SO ridiculously thick it’s unreal. I found it pretty much impossible to spread out and don’t even get me started on the brush strokes that were horrendously visible. It was a very difficult paint to work with and every time I went back over a section of paint to add more paint next to it (like you would, when you’re painting), it almost blistered and left a bumpy surface. I was really struggling! My first impressions weren’t great and I had some serious buyers regret. It was a bit of a learning curve to say the least.

blistering intumescent paint
So I then opted for a small sized sponge roller, which applied the paint sooooo much better. After two layers of bad application, I had to add a few several layers to mask the brush strokes, but the texture and finishing surface was infinitely better. If you’ve ever seen painted steel before (often found in warehouses), it always looks coated – and I now know why. This paint is like tar!
So, a quick few tips for application:
  • Make sure to keep stirring the paint – One of the reasons my brush application went horribly wrong was because the paint kept thickening in the tub. One good stir is not enough to keep it at a workable thickness, you have to remember to keep stirring it every now and then.
  • Use a roller, not a brush – Using a roller really helped to deal with the whole brush stroke problem. I was able to apply the paint much thinner and quicker with a roller. You will need more coats, but it’s definitely worth it! I actually used a sponge type roller which I think helped loads!
  • Don’t be tempted to add another coat too soon – This paint blisters like crazy with a paint brush, even if you add more paint just 2 seconds later. Be sure to let the paint dry thoroughly between coats or you’ll end up with bumps all over the place.
  • Use more paint than you think you need – So we needed to use 2/3 of the tub, which quite frankly was just an awkward measurement. You definitely don’t want to use less paint than required, so to be on the safe side I highly recommend using a bit more paint than you think you need.
  • Sand/Scrape off any imperfections between coats – If you do have any blistering or lumps and bumps, you can sand or scrape these off between coats. It’s not really a sand-able paint, but if you work at it, you can reduce any imperfections this way if things don’t go quite to plan.
If I were to expose a steel beam again, I think I would try another brand called ‘bro-steel’ by Bollom which claims to be “ultra-thin”. After discovering just HOW thick this paint really is, this certainly sounds like a winner to me.
painted steel
intumescent paint on steel beam
white painted steel beam
how to make a feature of a steel beam

Can You Add Colour?

The intumescent paint I’m using (and almost all the other brands I came across) claim you MUST use their brand finishing coat to add colour and cannot use regular paint over the top. How true this actually is, I’m not so sure. The finishing paint I’m using by by zero flame has absolutely no fireproofing properties, so it really doesn’t add any other layer of protection, which is why I question this.
Non-the-less, we do need this steel beam to be signed off by building control and I certainly didn’t want to take any chances, so we did opt for their CRAZY overpriced finishing paint. Seriously – the cost for this was more than the damn intumescent paint!! This paint is really just like any other regular eggshell – it’s much more thin and watery, can definitely be applied with a brush, leaves no paint stokes and only needed a couple of coats to ensure a good spread of colour.
Considering a little goes a long way, I WISH they had sold a much smaller tin. A 2.5L tub for this size steel is absolutely crazy and I virtually have the entire tin left. We’ve gone for a colour called ‘copper brown’ which funnily enough, is pretty much almost the same colour as the steel beam was originally. There’s plenty of colours to choose from, but sadly no testers so it was a bit of a risk anyway. To be honest, if I change my mind on the colour – I will probably just use a regular eggshell paint over the top. It’s the bottom layer that does the protecting and I can’t really see how a finishing coat could really affect that. Don’t take my word for that though! And do let me know if you know any reasons otherwise why this might be a bad idea!?
painting a steel beam
fireproofing a steel beam with paint
colouring a steel beam
exposed steel beam
steel beam feature in kitchen
diy painting a RSJ steel

How to get Certification and Sign off?

Now that your steel beam is fully fire-protected, you can finally apply for a sign off. The paint I’ve used comes with an application to acquire a certificate from the paint company. You simply fill in details such as surface area, type of beam, date of application and sign a pledge agreement to state that the paint was applied to the proper specifications. You then send this off (with a fee of £6 – bit cheeky considering the already extortionate cost of paint!) along with the receipt for the paint and receive a certificate in the post which you can give to building control who will then be able to fully sign off the steel beam. It’s as simple as that – although I’m still yet to receive my certificate on account of only recently having sent it off. Whoops! Hopefully, it will be as simple as that though.
certificate for painted steel beam
So that’s everything! Here’s a few shots of the finished steel beam in all its painted glory! We do actually intend on putting some bolt caps over the nuts and bolts for a more sleek finish. I’m pretty pleased with it otherwise – I just hope it doesn’t look too out of place when we get to having a finished kitchen…. It’s not exactly industrial themed, so hopefully the two different styles we’re now going for will gel together okay. (eep!)
RSJ painted beam
exposing an RSJ with paint
steel beam feature in kitchen
painted steel beams
What do you think? Yay or Nay? Should I have picked a more daring colour? And would you expose a steel beam in your home?
Costs
(rounded to the nearest pound)
New Tools Purchased:
Brushes £4
Roller and Tray £2
Materials Used:
Intumescent Paint £52
Finishing Eggshell £60

Total: £119
Kezzabeth

All posts

22 Comments

  • Paul Clappison September 14, 2020 at 8:52 am

    What an excellent and very informative blog, thank you so much.

  • Stephen October 4, 2020 at 8:55 pm

    Really helpful information thank you – I’m thinking of exposing a steel beam in my hallway.

    Do you have any pictures of it all finished ? 🙂

  • Annie Charman October 7, 2020 at 1:09 pm

    Hi, this is really useful advice, thank you. Did you use a primer on the steel beam before the intumescent paint?

    • Kezzabeth October 8, 2020 at 11:04 am

      No we didn’t use a primer, just went straight on with the intumescent paint 🙂

  • LEIJTEN November 10, 2020 at 12:04 am

    Comprehensive description of how to leave a RSJ exposed. Very useful! Thank you.

  • Jools Owen March 4, 2021 at 2:44 pm

    Really helpful article! Thanks for writing! On your advice I went with Bollom Brosteel Ultra 60. I have to confess it was still a little like painting on polyfilla rather than paint, but still sounds better and easier than the brand you went with… I also found them really helpful via email in specifying amounts and products for the job, even recommending a brushing technique for application which worked a treat. Then when I applied for the certificate afterwards (again by email) they got one back to me almost straight away! The same will most probably not be true of building control… I live in hope though! 🙂

    • Kezzabeth April 4, 2021 at 12:43 pm

      Haha ohh sounds like any intumescent paint is just awful to use then! I’m definitely going to give that one a try next time though, sounds like really great customer service you received too! Thanks for sharing and I hope building control haven’t taken months to sign it off for you!

  • Sean Taylor March 23, 2021 at 11:26 pm

    Hey this is brilliant.
    I have done exact same thing. Can I ask my steel is already in, I have had building control sign off the first part to say it’s been put in ok.
    I read somewhere you have to paint it before you put it in.
    Was your one installed before you painted it?

    Thanks again for this advice soooooo helpful.
    Thanks
    Sean.

    • Kezzabeth April 4, 2021 at 11:46 am

      Hi Sean!

      We spoke with building control about this and they were happy for the steel to be painted after installation. I would say it’s probably much easier to paint beforehand though! You can get companies to paint/fireproof the steel when they’re made to size, so that might be something worth looking into. We decided to expose ours after it was installed, hence painting afterwards! But yes, our building control signed it off with it being painted after installation.

      • Sean Taylor April 4, 2021 at 10:03 pm

        Hi
        Thanks so much again.
        Paint delivered so it will be an Easter Monday painting the steel day.
        As the weather is meant to be much colder.
        Thanks again.
        Kind Regards
        Sean

  • Michael Page April 29, 2021 at 10:19 pm

    Thanks for such an informative read, we’re currently having our kitchen and extension redone with exposed beams but building control told us we had to have a specialist paint them before installation and that they’d need to be covered up to be signed off.
    Am going to enjoy bringing this back up, will be gutted if they insist, when clearly it can be done.

    • Kezzabeth June 7, 2021 at 2:24 pm

      Perhaps they’ve changed the regs since we did ours. I know a few people who were able to paint the beam after installation, but this was a few years ago now. Fingers crossed they let you!

  • Yildiz May 30, 2021 at 6:46 pm

    We want to do ours but our building control guy telling us the beam has to be painted on all sides therefore we need to remove the beam, we are like how can qe remove it ? It carries the wall.
    We are quite confused.

    • Kezzabeth June 7, 2021 at 2:26 pm

      That’s a shame, they may have changed the regulations since we did ours? Or perhaps the guy certifying ours just didn’t care, haha! I’ve heard lots of different councils request different things, so it doesn’t seem to be the same across the board – although you’d think it should be!!

  • Les June 8, 2021 at 6:17 am

    Good info thanks. Just put up my steel girder up (what a job!). Spoke to a local builder about my thoughts on having it exposed and he thought that different query ideas and variations can really had to the overall look. For example I’m soon installing an oak beam above a fireplace I’ve opened up. Anyone Spoke to my local building control today about fire protection paint and he told me I was barmey but its allowed. All I need is to get a 30 minute fire rated paint. And for the next inspection to show them the paint, receipt and proof its 30 minute or better fire rated. I havnt bought any paint yet but I’m seeing if there is a spray on option as it seems when brushing it on it leaves streaks. The alternative is to find a clear intumescent lacquer spray on (if it exists) where I can spray over the primed original copper /red/brown colour. The other issue I need to consider is it was only single wall thick. So the RSJ completely overs the width and a little more by a few mm, so when I’ve dry lined the walls the rsj will be slight inset with me not boxing it in.

    • Kezzabeth June 30, 2021 at 10:00 am

      Love the idea of a clear intumescent paint to keep the original look of the steel – hope you’ve managed to find something! The colour we went for was very similar to the original steel, hadn’t considered looking for something clear. I know a few people who have paid to have their painted by a company who used a spray, but I don’t know if the same paint is available on a DIY level. Would be interested to hear what you’ve done in the end – and hope it’s all gone well for you!

  • Ryan October 29, 2021 at 8:40 am

    Hi
    Did you use a primer before putting the Intumescent Paint on?
    If so which primer did you use?
    Thanks great blog

    • Kezzabeth November 4, 2021 at 9:48 pm

      Hey! No we didn’t use a primer, just straight on with the intumescent!

      • Keith December 3, 2021 at 4:49 pm

        Hi. Has building control signed off on your exposed steel now that it has been fire proofed?

        • Kezzabeth December 13, 2021 at 8:59 pm

          Yes, they inspected it and signed it off 🙂

  • Sarah February 9, 2022 at 11:30 am

    We’re just about to do this to three beams in our house so I’m so glad I read this before ordering paint etc. So helpful. Thank you! Love how your beams turned out.

  • Leave a Reply

    This site uses Akismet to reduce spam. Learn how your comment data is processed.

    Hey!

    Hey!

    Hi - I'm Kezzabeth! Self-taught DIYer, Renovator and Blogger on a mission to turn our house into a home. Seven years ago I was clueless and skill-less, but since then I've learnt how to build, tile, plumb and more. This is my little place on the web where I share everything I've learnt so you can learn too. Read More

    Subscribe to the Newsletter

    Never miss a post - Subscribe for monthly updates!

    Privacy Policy

    Favourite Projects

    Follow Me On Instagram: @Kezzabeth_blog

    Disclaimer

    DIY Content: We’re not builders or experts in the trade industry, so please take any information on this blog as a rough guide and just our own experiences. This blog relates to our home only and you should always consult a professional in you’re in any doubt of work. Please also be aware Building Regulations change often, so always do your own research as well.
    ×