Structural engineering for two-storey extensions in Renfrewshire and Inverclyde

Renfrewshire and Inverclyde at a glance

Nation: Scotland
Price region: Scotland
Postcode areas: PA
Towns covered: 10 listed below, plus surrounding villages
Site visits: Free, no obligation

What a structural design involves

This service suits every two-storey extension, because each one needs foundations sized for two storeys and usually steel beams where walls are removed. You get a structural engineer's calculations and drawings for beams, padstones, lintels, foundations and connections, coordinated with the architectural drawings, submitted for building standards and followed through on site by our build teams.

The main places we list in Renfrewshire and Inverclyde are Paisley (PA1), Greenock (PA15), Renfrew (PA4), Johnstone (PA5), Erskine (PA7) and Port Glasgow (PA14). We cover the villages in between too.

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.

Beams and padstones

Steel beams carry the first floor and roof over openings, and they sit on padstones that spread the load into the walls. The engineer sizes each beam and checks the walls can take the point loads, which affects ceiling heights and where posts can go.

How we work in Renfrewshire and Inverclyde

Free site visit
We visit your home in Renfrewshire and Inverclyde, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Drawings, then consent
We draw the scheme, check it against the rules in Scotland, and take it through the right consent with the council.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
On site
One project lead runs the job, keeps you updated and arranges inspections at each stage until completion.

Towns we cover in Renfrewshire and Inverclyde

Structural engineering for two-storey extensions in Renfrewshire and Inverclyde: 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 Renfrewshire and Inverclyde · About structural engineering for two-storey extensions