Bi-fold & sliding door openings · Renfrewshire
Bi-fold & sliding door openings in Renfrewshire
Survey, engineer's design and installation of bi-fold & sliding door openings anywhere in Renfrewshire.
- Free survey visit in Renfrewshire
- Engineer's calculations arranged
- Building warrant handled for you
- Free survey visit
- Engineer's calculations arranged
- Building control handled
- Fixed written price once scope is agreed
- England, Wales, mainland Scotland & NI
Bi-fold & sliding door openings in Renfrewshire: how it works
Bi-fold and sliding door openings are wide gaps formed in an external wall, usually at the back of the house, to take a run of folding or sliding glazed doors. A steel beam carries the wall, floor and roof loads above, and it is designed stiff enough that its movement does not press on the glass or stop the doors running.
We carry out bi-fold & sliding door openings throughout Renfrewshire, for homeowners, landlords and builders who need the structural part done properly. We work in Johnstone, Renfrew and Erskine and the surrounding villages. You get an itemised written quote that shows the calculations, approvals, steel, labour and finishing as separate lines.
Key points for your project
- New glazed doors must meet the energy efficiency requirements of the building regulations, and a wide opening adds a large area of glazing to the house. The door supplier normally provides the performance data that building standards needs.
- New brickwork at the reveals and above the opening should match the existing in colour, size and bond. Sound bricks from the wall being removed are often cleaned and reused, and the mortar colour is matched as closely as possible.
- The structural work for a typical bi-fold opening usually takes three to five working days. Doors are often made to order, so the steel goes in once opening sizes are confirmed and the doors are fitted soon after.
- In cavity walls a cavity tray above the new head directs any water in the cavity out through weep vents. Without it, damp can show inside above the doors, so the tray is lapped and sealed correctly as the brickwork is rebuilt.
- Level or flush thresholds are popular with bi-fold doors, but the floor inside and the patio outside need planning together. Drainage at the threshold and a proper damp-proof detail stop water running in when the outside is close to floor level.
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 warrant
A building warrant is applied for from Renfrewshire Council, and work starts only once the warrant has been granted.
Fit, inspect, finish
The work is propped and the steel installed and packed tight. After inspection the opening is boxed, plastered and left clean.
How much should I budget in Renfrewshire?
As a guide, budget £2,300–£6,350 including VAT for rear wall opening for bi-fold or sliding doors in Renfrewshire, based on published UK cost guides adjusted for prices in Scotland (-9%).
| Job | Typical guide range | What it usually covers |
|---|---|---|
| Rear wall opening for bi-fold or sliding doors | £2,300–£6,350 | External wall opened up to about 5 m with steel, propping, cavity tray and making good (doors supplied separately) |
| 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) |
| Widening an internal doorway | £910–£2,280 | Opening widened with a new lintel or short beam, approval where structural, and making good |
| Structural calculations for a beam | £230–£680 | Site measure or photos, beam and padstone design and calculations for building standards |
Figures include our approximate regional adjustment for prices in Scotland (-9%) and are rounded. How these figures are worked out.
Approvals in Renfrewshire
Steel beam work in Renfrewshire needs a building warrant from Renfrewshire Council. The structural design is part of the application, and the council's building standards team accepts the completion certificate once the work is done as approved.
Scotland has no Party Wall Act. Work affecting a shared wall is governed by your title deeds and the general law, and in flats by the Tenements (Scotland) Act 2004, so it is sensible to agree the work with neighbours in writing before starting.
Local questions answered
What happens at the survey visit in Renfrewshire?
We look at the wall, the floor and ceiling either side and what sits above, measure the opening you want, and note cables, pipes and access for the steel. It usually takes under an hour and there is no charge.
Can I stay at home while the work is done in Renfrewshire?
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.
Should I order my doors before the opening is made?
It helps to choose them first. The supplier's structural opening size and threshold detail feed into the steel design, so the opening is formed to suit the doors exactly. Many people order once the engineer has confirmed the opening, then time the structural work so the gap is weathered for as short a time as possible.
What does a bi-fold opening quote include?
Our itemised written quote covers the survey, calculations, building standards, propping, removing the wall, steel and padstones, outer leaf support, cavity trays and closers, temporary weather protection and making good. Doors, threshold drainage and patio work are shown separately unless agreed. The price is fixed in writing once the opening size and specification are agreed.
How wide can a bi-fold door opening be?
There is no fixed limit, as it depends on the loads above and what the beam can bear on. The engineer designs the steel and, for very wide openings or ones near a corner, may specify columns or a goalpost frame. The door system's own maximum panel sizes and configurations also need checking.
Do I need building regulations for bi-fold doors?
Yes, when you are making a new or wider opening in an external wall, because that is structural work. Building standards also checks the doors meet energy efficiency and safety glazing requirements. In Scotland a building warrant is needed before the work starts. Replacing doors like for like in an existing opening is different and is often handled through an installer's competent person scheme.