Structural engineering for two-storey extensions in Argyll and Bute

Argyll and Bute at a glance

Nation: Scotland
Price region: Scotland
Postcode areas: G, PA
Towns covered: 8 listed below, plus surrounding villages
Site visits: Free on the mainland; island and remote addresses by arrangement, with travel costs agreed first

What a structural design involves

Structural engineering for a two-storey extension involves calculating how the new floors, walls and roof carry their loads down to the ground, and designing the beams, lintels, foundations and ties into the existing house to suit. The engineer's calculations and drawings form part of the a building warrant. They also tell the build team exactly what steel and foundations to install.

Across Argyll and Bute we cover Helensburgh (G84), Dunoon (PA22), Oban (PA34), Rothesay (PA20), Campbeltown (PA28) and Isle of Islay (PA43), plus the smaller places around them.

Fees

A structural engineer (calculations and beam design) is a guide of £750–£2,200, priced in writing once the design is known.

Rules in Scotland

In Scotland, structural calculations form part of the building warrant application, assessed against the Scottish Building Standards Technical Handbooks rather than Approved Documents. The council's building standards service must grant the warrant before any structural work starts, and a completion certificate is submitted when the work is finished.

Approval in Scotland: Householder planning application: £371. Councils have two months to decide a local planning application.

Building standards: A building warrant from the council's building standards service before work starts, and a completion certificate at the end. Scotland uses its own Technical Handbooks.

There is no Party Wall Act in Scotland. Shared walls and boundaries are governed by title deeds and common law, so we speak to neighbours early and record the condition of shared structures.

Getting the design right

Tying into the house

The new walls and floors are tied into the existing house with wall ties, restraint straps and joist hangers. The engineer also considers movement between the old and new foundations and where a movement joint may be needed.

Foundations for two storeys

Two storeys put more load on the ground than one, so foundations are usually deeper or wider. Clay soil, nearby trees, drains and made-up ground can all mean deeper trench fill or piles, which is why we dig trial holes before fixing the design.

How we work in Argyll and Bute

Free site visit
We visit your home in Argyll and Bute, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in Scotland before drawing in detail.
Engineer it
Foundations sized for two floors, steels for any openings, and a building warrant, all before anyone starts on site.
Build and sign-off
Vetted teams working under S&K build the extension, and we arrange the completion certificate at the end.

Towns we cover in Argyll and Bute

Structural engineering for two-storey extensions in Argyll and Bute: questions

What are trial holes and why do I need them?

Trial holes are small excavations dug next to the house or garage to see the depth and condition of the existing foundations and the soil. They tell the engineer whether existing footings can be reused and how deep the new ones need to go, which avoids surprises during the build.

Do I need a structural engineer for a two-storey extension?

Almost always. Building standards needs calculations showing that the foundations, beams and walls can carry the loads of two storeys and a roof. A two-storey extension usually involves removing part of an outside wall and new steel, which needs an engineer's design.

Will the engineer visit the site during the build?

Not usually at every stage. Building standards inspects the foundations, steelwork and other key stages against the approved calculations. The engineer is called back if site conditions differ from the design, such as unexpected ground, hidden beams or weak existing walls, and issues revised details before that part of the work continues.

Neighbouring areas

All extension services in Argyll and Bute · About structural engineering for two-storey extensions