RSJ installation · Porthmadog
RSJ installation in Porthmadog
RSJ installation in Porthmadog, from free survey to completion certificate.
- Price fixed in writing once scope is agreed
- Building control arranged
- Temporary works and making good included
- Free survey visit
- Engineer's calculations arranged
- Building control handled
- Fixed written price once scope is agreed
- England, Wales, mainland Scotland & NI
What RSJ installation involves in Porthmadog
Our RSJ installation service in Porthmadog covers everything from the first visit to the completion paperwork. The wider Gwynedd area is covered as well. Postcode districts we cover here include LL47, LL48 and LL49.
People still call almost any steel beam in a house an RSJ, even though the sections fitted today are usually universal beams with parallel flanges. Whatever the name, the job is the same: a length of structural steel, made to an engineer's specification, carrying floors, walls or roof over a space where support used to be.
Worth knowing before you start
- Sometimes two beams are bolted side by side with spacers, either to carry a thick wall or to fit through a tight space. Bolt spacing and spacer type come from the engineer's design rather than being decided on site.
- Floor joists can rest on the bottom flange, hang from timber packers bolted into the web, or be notched to sit over the steel. The engineer specifies the connection, and it affects how flush the finished ceiling can be.
- Where a long beam cannot be carried into a property in one piece, the engineer can design a bolted splice so it arrives in two or more lengths. The splice position and bolts are part of the calculations and must be installed exactly as drawn.
- An RSJ inside a home commonly needs 30-minute fire resistance where it supports elements of structure. Fire-rated plasterboard boxing is the usual method, with intumescent paint used when the beam is to remain visible.
- Packing is what makes the beam work. Steel shims and dry-pack mortar fill the gap between the top flange and the structure above, so the load transfers onto the steel without the floor or wall settling down onto it.
What happens, step by step
Look and measure
We check the wall, the span you want and what the wall is carrying, and photograph anything the engineer needs to see.
Design and price
Calculations come back from the engineer and we confirm your fixed written price, line by line.
Building control
We submit the application or notice to Cyngor Gwynedd under the Building Regulations as they apply in Wales, before work starts.
Fit, inspect, finish
The work is propped and the steel installed and packed tight. After inspection the opening is boxed, plastered and left clean.
What does RSJ installation cost in Porthmadog?
As a guide, budget £730–£2,280 per beam including VAT for rSJ supply and fit (single beam) in Porthmadog, based on published UK cost guides adjusted for prices in Wales (-9%).
| Job | Typical guide range | What it usually covers |
|---|---|---|
| RSJ supply and fit (single beam) | £730–£2,280 per beam | Beam supplied, delivered, lifted and packed on padstones, with propping (calculations and approval priced separately) |
| Load-bearing wall removal with steel beam | £1,800–£4,550 | Typical internal wall up to about 4 m: calculations, building control, propping, steel, padstones, fitting, fire protection and making good |
| Steel beam replacement | £1,800–£5,000 | Propping, removing the failed beam, new steel on proper bearings, approval and making good |
| Structural calculations for a beam | £230–£680 | Site measure or photos, beam and padstone design and calculations for building control |
Figures include our approximate regional adjustment for prices in Wales (-9%) and are rounded. How these figures are worked out.
Approvals in Porthmadog
Welsh building regulations treat beams and new openings as controlled building work. We apply to Cyngor Gwynedd on your behalf before anything is removed, give the commencement notice the 2026 Welsh rules require, and the steel is checked before it is boxed in.
Where the steel bears into a wall shared with next door, notice must be served under the Party Wall etc. Act 1996. If your neighbour dissents, surveyors agree how the work is done before it starts.
RSJ installation near Porthmadog
- Pwllheli 12.2 mi
- Caernarfon 15.8 mi
- Dolgellau 16.5 mi
- Bangor 20.7 mi
- Menai Bridge 20.7 mi
- Bala 22.4 mi
Local questions answered
Who approves RSJ installation in Porthmadog?
Structural work in Porthmadog needs a building control application to Cyngor Gwynedd under the Welsh regulations, with a commencement notice before work starts. We prepare and submit it with the structural engineer's calculations and arrange the inspections, so the completion paperwork follows the job.
Do I need a party wall agreement for RSJ installation in Porthmadog?
Yes, if the beam bears into a shared wall: the Party Wall etc. Act 1996 applies in England and Wales, and a party structure notice must be served at least two months before that work starts. We arrange it through a party wall surveyor.
Does an RSJ need to be painted or boxed in?
Usually it needs fire protection, most often by boxing in with fire-rated plasterboard and skimming. If you want the steel on show, an intumescent paint system can be applied to the specified thickness and then top-coated in your chosen colour. The fabrication primer is not fire protection on its own.
Can an RSJ be delivered in sections?
Yes, where access is tight. The engineer can design bolted splice joints so a long beam arrives in two or more pieces and is joined in place. The splice has to be part of the calculations from the start, because it changes how the beam carries load at that point.
Is an RSJ the same as a steel beam?
In everyday use, yes. Builders and homeowners call most steel beams RSJs, whether they are universal beams, channels or columns. Technically an RSJ is one particular older section shape, but the engineer's drawing names the exact section type, so there is no confusion on site.
Can I stay at home while the work is done in Porthmadog?
Usually, yes. The work area is screened and floors are protected. The rooms either side of the opening are out of action for a few days, and there is some noise and dust while the masonry comes out.