Frequently Asked Questions

Answering your questions about Intrastack and LGSF

Here we answer the most frequently asked questions about us and our steel frame solutions. If you are unable to find the answer to your question on this page, please get in touch and we will be happy to help.

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How many storeys can you build up to? 

Up to 12-storeys of LGSF structure. This can sit on the ground floor slab or on a podium structure.

What is the lead-time from design to on-site?

Typical programme is 14 – 16 weeks from architect drawings being frozen.

What warranties do you provide? 

We can provide a standard manufacturers’ collateral warranty or sign up to the main contractors’ collateral warranty (following legal review).

What accreditations do you have?

SCI/ NHBC Stage 1, Advantage, Checkmate (LRH), Premier Guarantee, LABC Warranty.

Do you have your own installation team for projects? 

No, but we do have a list of approved installers that we can recommend.

Do you include windows in your walls? 


What comes in the pre-made wall panels? 

External – steel frame, studs, tracks and x-bracing (where necessary) and sheathed to the external face with 12.5mm Glasroc X.

Internal – steel frame, studs tracks and x-bracing (where necessary), hot-rolled columns (where necessary).

At what design stage do you get involved?

As early as possible.

What wall build-ups do you have available? 

A variety to accommodate both multi-storey multi-occupancy and low-rise housing, both load bearing and non-load bearing walls. Build-up requirements depend on what fire performance is needed above standard Part B requirements and/ or the thermal value required. Tested build up data is available in our Intrastack brochure.

Do you offer a modular solution? 

We do not provide modules, but we can assist with modular companies by providing them with panels to build their modules.

What roofing options do you offer? 

LGSF Cassettes, composite concrete deck, timber trusses or i-Roof (for low rise).

Can you do extensions? 

Yes – as a light-weight solution our system is ideal for extensions as existing structure reinforcement can be kept to a minimum.

Can you do hybrid buildings? 

Yes – we offer an SFS infill system to support the external façade on concrete or hot rolled primary frame structures.

We can also offer options where we combine hot and cold rolled steel to provide a load bearing solution.

We also work with our Saint-Gobain sister brands to provide options for room-in-roof solutions or timber truss roofs.

What are the main benefits of the system? 

  • Speed of construction and increased productivity.
  • Weight reduction – can be up to 70% lighter than traditional builds.
  • Design flexibility.
  • Site safety – OSM is unaffected by adverse weather and reduces site labour & working at height – increasing on site safety.
  • Lifespan – LGSF structures have a lifespan of in excess of 60 years, being a dry process which won’t shrink or warp under load.
  • Stability – The system offers dimensional stability.
  • LGSF is non-combustible and as such fire protection is not required during construction.
  • Accuracy and reduced waste – Precision engineered providing accurate dimensions and significantly reducing waste.
  • Option for composite (concrete) decking for all floors and can assist in achieving acoustic values beyond regulatory requirements.

How does payment work? 

Payment terms are 30 days from invoice. (Note: due to the off-site nature of our work we require payments for materials and fabrication for off-site manufacture). Payment terms are subject to satisfactory financial checks.

How do you support me on-site? 

Intrastack works closely with installers and contractors to ensure seamless delivery and installation. A Technical Project Manager (TPM) will be assigned to manage timelines and project details, and they will be on-site at certain points throughout the installation to ensure system details are adhered to.

Who signs off the building? 

The Intrastack team can assist by visiting site during build phases and on completion of steel erection to offer guidance and to sign-off the steel installation; Building Control have ultimate sign-off.

Who is responsible for the design? 

Intrastack is responsible for the design of the LGSF structure.

What is the lifecycle on the Intrastack panels? 

The NHBC and other housing warranty providers accept LGSF structures as having a life span in excess of 60 years, however the predicted life span of a steel framed building with warm wall construction is over 250 years. At the end of their life the panels can be recycled. The Intrastack panels are also demountable so have the potential to be removed from an existing structure and being reused in another similar one.

What long term maintenance is needed for the Intrastack system and what would this entail?

Inspections should be carried out, and any damaged areas of the galvanisation protection, e.g. at weld zones, must be reinstated by treatment with an appropriate zinc-rich paint.

How sustainable is the system? 

  • Reduction in transport/ logistics.
  • Lightweight steel frame structure can be up to 70% lighter than traditional  material structures.
  • Precision manufacturing (components are rolled to required lengths), which reduces material waste.
  • Embodied carbon reduced up to 20%.
  • LGSF can achieve significantly higher levels of thermal insulation than traditional builds.
  • LGSF structures can be modified and extended – widely used for building extension & renovations.