Dreaming about busting through that wall at home?
Planning an extension or loft conversion? You’re going to need an RSJ (Rolled Steel Joist) to hold up your property. Steel beams like these are used in most construction projects where structural work is involved.
The issue is:
Most homeowners have no idea which RSJ they need or how much it should cost. That’s when things get expensive. Reading up on the RSJ installation cost basics before you start your project can help you save thousands. Plus it’ll save you from making costly mistakes that could affect the structural integrity of your property.
What’s in this guide:
- RSJ Types and Usage
- How To Choose The Right Size
- Cost Factors and Prices To Expect
- DIY Vs Professional Installation
What Is An RSJ And Why Is It Important?
An RSJ is a type of steel beam used in construction work to support loads when you take out walls or open up spaces.
They’re also referred to as I-beams or H-beams due to their shape. These beams help to distribute the weight of floors, roofs, and walls above so that your building doesn’t collapse when you make structural alterations.
Fact:
Whenever you see an open-plan kitchen or a wide doorway in an older property, there’s a good chance that there is an RSJ behind the scenes providing the strength and support. Steel construction maintains a 94.1% market share in industrial single-storey buildings for good reason — it is unbelievably strong and dependable.
Types Of RSJs Explained
Not all RSJs are the same.
Different construction projects require different types of steel beams. Allow me to elaborate on the main types…
Universal Beams (I-Beams)
These are by far the most common RSJs you will come across. They are shaped like a capital letter “I” and are used for horizontal purposes such as supporting floors and roofs.
Universal beams are the most cost-effective and versatile option, making them suitable for most residential projects. They offer great strength without being too heavy.
Universal Columns (H-Beams)
As the name suggests, universal columns have the same depth and width, making them look like an “H”.
They are used more vertically as columns, but can be used horizontally when vertical space is limited. These beams are a bit more expensive than universal beams but offer higher load-bearing capacities in certain scenarios.
T-Beams and Lintels
T-Beams are less common in residential projects but can provide extra structural support where needed.
Lintels are the horizontal beams that you already have over your doors and windows. They can be made from timber, stone, brick, steel or reinforced concrete.
How To Pick The Right RSJ Size
Here’s what most people get wrong:
They just assume any old RSJ will do. Wrong. The size and weight capacity of your RSJ must be tailored to your specific project requirements.
A structural engineer will be able to calculate the exact specifications based on:
- The length of the span (the distance the beam needs to cover)
- The load it needs to support (weight from above)
- The existing structure of your building
- Local building regulations
Never try to guess which RSJ size you need. The consequences of getting it wrong can range from expensive repairs to complete structural failure.
RSJs have been around since 1849 as part of the structural steel market valued at $105.57 billion in 2022. They have been a construction staple for a reason.
Real RSJ Installation Costs
So what are we actually looking at for costs?
For most homeowners in the UK, RSJ installation costs range between £1,000 and £1,800. But that is just a starting point. Your actual costs will vary wildly based on several factors:
Beam Size and Weight
The larger and heavier your RSJ, the more you will pay. Small beams of around 1 metre in length for doorway removals will cost considerably less than 5-metre beams for large open spaces.
Expect to pay around £3.50 per kilogram for the steel itself.
Labour Costs
Installation isn’t cheap, as it requires skilled professionals and specialist equipment. RSJs are extremely heavy — some weigh in the hundreds of kilograms — so they need proper lifting equipment.
Installation labour will typically cost between £300 to £750 depending on the project size.
Additional Costs
Don’t forget the often-overlooked costs such as:
- Structural engineer fees (£300-£800)
- Building regulations approval (£160-£325)
- Wall removal and disposal
- Plastering and finishing work
- Fire protection (plasterboard or intumescent paint)
DIY Your RSJ Installation?
Short answer: No.
Longer answer: Absolutely not.
RSJ installation is not a DIY project as it requires specialist knowledge, equipment and building regulations compliance. These beams support the entire structure of your home. One mistake could result in catastrophic failure.
Professional builders and structural engineers are worth every penny, as they:
- Precisely calculate load requirements
- Ensure building regulations compliance
- Use proper lifting and installation equipment
- Provide certification for future property sales
- Carry insurance for the work
Even if you are a dab hand at DIY projects, RSJ installation isn’t the place to cut costs. The risk isn’t worth it.
Hiring The Right Professional For The Job
Finding a qualified builder or structural engineer is key. Firms such as Atlanta fence and deck often collaborate with structural engineers when projects involve altering load-bearing walls or supporting major exterior features.
Look for professionals that:
- Have relevant experience with RSJ installations
- Carry the proper insurance
- Provide references from previous projects
- Provide detailed written quotes
- Have knowledge of local building regulations
Get at least three quotes before making a decision. Be wary of quotes that seem too good to be true — they usually are.
The cheapest option often ends up costing you more in the long run when problems inevitably arise.
Building Regulations and Compliance
Every RSJ installation needs to be approved by building control.
Your structural engineer will submit plans and calculations to the local authority for approval. After installation, you will need an inspection to get a completion certificate.
This certificate is crucial when you go to sell your property. Buyers and mortgage lenders will want proof that structural work was done properly and legally.
The entire approval process can take several weeks, so allow for that in your plans.
Common Mistakes With RSJ Installation
Mistake #1: Skipping the structural engineer
Some homeowners think they can save money by doing the structural calculations themselves. Don’t do this. It’s both dangerous and potentially illegal.
Mistake #2: Choosing the wrong beam type
Not all RSJs are suitable for all applications. Using the wrong type of beam can lead to structural issues further down the line.
Mistake #3: Ignoring fire protection
Building regulations require RSJs to have a minimum of 30 minutes fire resistance. This typically means boxing them in with fire-rated plasterboard or using intumescent paint.
Mistake #4: Poor project planning
RSJ installations are not a one-day job. You need structural engineers, building control approval, builders and plasterers — all working in sequence.
Wrapping It All Up
Choosing the right RSJ is not difficult when you know the basics.
Start with a qualified structural engineer who can calculate your exact requirements. Get quotes from reputable builders and don’t try to cut corners. Follow building regulations to the letter.
Don’t forget these important points:
- Never skip the professional calculations
- Always budget for the full range of associated costs, not just the beam
- Allow time for building control approval
- Use qualified professionals with proper insurance
- Keep all documentation for future property sales
RSJ installation is a worthwhile investment in your property. Done correctly it can open up your living space and add value to your home. Done incorrectly it can be dangerous and expensive to put right.
Take your time, do your research and work with professionals who know what they are doing. The structural integrity of your home depends on it.