How FMB-accredited Dentone Builders install and insulate structural steel beams (RSJs) to open up rear extensions for homeowners in Stamford, Lincolnshire.
Once the foundations of a Stamford extension have cured and the blockwork has started to rise, the next milestone is the one that makes an open-plan kitchen-diner possible in the first place: structural steel. If you’ve ever wondered how a Stamford, Lincolnshire extension ends up with a wide opening into the garden instead of a row of load-bearing walls, the answer is steel beams, sized and positioned by a structural engineer and installed by an experienced local building team.
On a recent project, our team lifted and bolted rolled steel joists (RSJs) into place across the rear of the property to carry the load of the wall and roof above a new, wide opening. Each beam sits on padstones built into the existing blockwork, spreading the load safely down into the foundations poured during the groundworks stage. Getting this step wrong isn’t a cosmetic issue — it’s a structural one, which is exactly why it should only ever be carried out by builders who work to calculations from a qualified structural engineer.
Insulating and Boxing In the Steel
Once each beam was fixed, our team packed insulation around it before the blockwork closed in around the steel, preventing it from becoming a cold bridge that could lead to condensation inside the finished room. This detail is easy to miss and rarely visible in a finished extension, but it directly affects how comfortable and energy-efficient a Stamford home is once the kitchen or living space is complete.
Why Homeowners in Stamford Should Ask About This Stage
When comparing extension builders in Lincolnshire, it’s worth asking directly how structural steel will be specified, who calculates the loadings, and how the beams will be insulated. As a Federation of Master Builders member, Dentone Builders’ structural work on every extension is carried out to Building Regulations and signed off by building control, giving Stamford homeowners confidence that what’s holding their new extension up was done properly — not guessed at.
Dentone Builders is a Federation of Master Builders (FMB) accredited building company with over 40 years of construction heritage, based in Lincolnshire and serving homeowners across Stamford and the surrounding area. Every extension we build—from the structural steelwork onward—is backed by our FMB accreditation and a 10-year structural warranty.
Frequently Asked Questions
Do I need a structural engineer for steel beams in an extension?
Yes. Any steel beam carrying load from a wall, floor, or roof needs to be calculated by a structural engineer and approved by building control before it’s installed — this isn’t optional, and any Stamford builder proposing to skip it should be a warning sign.
Will structural steel make my extension cold?
Not if it’s detailed correctly. Steel conducts heat far more readily than blockwork, so it needs to be wrapped in insulation and isolated from the internal finish to avoid becoming a cold bridge — a detail Dentone Builders addresses on every steel installation.
Building an Extension in Stamford: The Full Series
- 1. Groundworks & Foundations: The Stage Every Stamford Extension Depends On
- 2. Structural Steel: How Stamford Extensions Get Their Wide, Open-Plan Spaces
- 3. Blockwork & Roofing: Making a New Extension Look Like It Was Always There
- 4. From Shell to Kitchen-Diner: Finishing a Stamford Extension
- 5. Why Choose an FMB-Accredited Builder in Stamford, Lincolnshire
Planning a house extension or renovation in Stamford or across Lincolnshire? Call Dentone Builders on 01780 693 799.