Bi-fold & sliding door openings · Powys
Bi-fold & sliding door openings in Powys
Bi-fold & sliding door openings across Powys, designed by a structural engineer and signed off by building control.
- Free survey visit in Powys
- Engineer's calculations arranged
- Building control 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
Planning bi-fold & sliding door openings in Powys
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.
Homes across Powys range from Victorian terraces to post-war semis and newer estates, and bi-fold & sliding door openings look different in each. We can survey in places such as Brecon, Llandrindod Wells and Welshpool and the villages around them. We plan the steel, the temporary support and the approvals around the building, then fix the price in writing once the scope is agreed.
Worth knowing before you start
- 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.
- Glazed doors need a stiffer beam than a plain opening of the same width. If the steel bends even slightly under load, folding panels can bind, sliders can stick and glass can be stressed, so the engineer sets a tighter deflection limit for door openings.
- 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.
- A wide glazed opening changes the security of the back of the house. During the works the opening is boarded at night if the doors are not yet fitted, and it is worth checking the locking and glass specification of the doors you choose.
- Replacing a rear window with doors in a house is usually permitted development, but front elevations, listed buildings, flats and homes where permitted development rights have been removed may need planning permission or another consent.
What happens, step by step
Free visit
A short visit to Powys to see the job, agree what you want and check the bearings, floors and services that affect the design.
Calculations
The engineer's calculations and a simple drawing are prepared for your opening and shared with you before anything is ordered.
Building control
We submit the application or notice to Powys County Council under the Building Regulations as they apply in Wales, before work starts.
Steel in, made good
On site we prop, open up, fit and pack the steel, then fire protect, box in and plaster once the inspection is done.
What do bi-fold & sliding door openings cost in Powys?
As a guide, budget £2,300–£6,350 including VAT for rear wall opening for bi-fold or sliding doors in Powys, based on published UK cost guides adjusted for prices in Wales (-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) |
| Structural calculations for a beam | £230–£680 | Site measure or photos, beam and padstone design and calculations for building control |
| Opening into a rear extension | £2,300–£6,350 | Original rear wall removed with a beam or goalpost, approvals and propping, coordinated with the extension build |
| 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) |
Figures include our approximate regional adjustment for prices in Wales (-9%) and are rounded. How these figures are worked out.
Approvals in Powys
Removing a load-bearing wall in Wales needs approval under the Welsh building regulations before work starts. For Powys the application goes to Powys County Council or a registered building control approver, with the engineer's calculations, and a completion certificate follows the final inspection.
The Party Wall etc. Act 1996 applies in Wales as well as England, so a beam bearing into a shared wall needs a party structure notice at least two months before work starts. We arrange notices through a party wall surveyor.
Bi-fold & sliding door openings by town
Bi-fold & sliding door openings in Powys: your questions
What happens at the survey visit in Powys?
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 Powys?
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.
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.
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.
Can I have a level threshold with bi-fold doors?
Often yes, but it has to be designed. The inside floor, outside paving and drainage all need to work together so water cannot run in, usually with a drainage channel outside and the right damp-proof detail under the door frame. We look at levels at the survey and plan the threshold with the door supplier.
Do I need planning permission for bi-fold doors?
Usually not for a rear opening in a house, as this generally falls within permitted development. Planning or another consent may be needed for front elevations, flats, listed buildings, conservation areas with extra controls, or homes where permitted development rights have been removed. We flag this at survey so you can check before work is booked.