Do I need planning permission for an extension?

Many single-storey rear extensions fall under permitted development, but the thresholds depend on your property type, its planning history and whether you are in a conservation area. We establish this at survey stage and tell you plainly which route applies before you commit to anything.

Can you work from my architect's drawings?

Yes. We price from existing drawings and structural calculations, and will flag any buildability issues before work starts rather than during. If you do not yet have drawings, we can introduce you to practices we work with regularly.

How long does a typical extension take?

A single-storey rear extension is commonly twelve to sixteen weeks on site once foundations begin, subject to size, ground conditions and inspection dates. Your programme is issued with the quotation, and you are told promptly if anything moves.

What happens if something unforeseen is found?

Unforeseen conditions — poor existing foundations, undocumented drainage, asbestos — are priced as a variation and agreed in writing before the work is done. Nothing is added to your bill without your sign-off first.

01 / CONSTRUCTION

Construction and structural works

Extensions, loft conversions and structural alterations, delivered with the drawings, the building control sign-off and the programme all held in one place.

Building work goes wrong in predictable ways: a price that moves once the floor comes up, a programme nobody owns, and three trades each waiting on the other. We built our construction service around removing those three failures.

Every project starts with a measured survey and a written scope, so the quotation you receive is the price we work to. One contracts manager stays with the job from setting out to handover, and the structural, mechanical and finishing trades are all ours to schedule.

Suited to

Homeowners adding space rather than moving
Landlords converting or reconfiguring stock
Buyers refurbishing before moving in
Commercial clients altering a unit's layout

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Quotation: Fixed and written
Drawings: Architect and engineer coordinated
Sign-off: Building control managed
Site contact: One named manager

Capabilities

What construction covers with us

Extensions and conversions

Single and double-storey rear extensions, side returns, wrap-arounds, loft conversions and garage conversions. We handle the interface between old and new — the part that determines whether the finished room reads as an addition or as part of the house.

Structural alterations

Wall removals, steel beam installation, chimney breast removal and openings formed in load-bearing walls, all executed to a structural engineer's calculations with the temporary works designed before anything is cut.

Groundworks and foundations

Excavation, foundation design and pour, underpinning, drainage diversions and slab construction, including the below-ground detail that building control will inspect before it is covered.

Full refurbishment

Whole-property strip-outs and rebuilds where the plan changes as well as the finishes — reconfiguring layouts, replacing services and bringing the fabric up to current standards in a single programme.

Scope of works

Specifically, we carry out

If what you need is not listed, ask. We cover London, Greater London, Essex, Hertfordshire, Kent and Surrey.

Single and double-storey extensions
Side return and wrap-around extensions
Loft conversions, dormers and rooflights
Garage and outbuilding conversions
Structural openings and steel beam installation
Chimney breast removal and support
Underpinning and foundation works
Excavation, groundworks and drainage
New-build residential shells
Whole-house refurbishment and strip-out

Related work

Construction case studies

Questions

Construction — the usual questions

Do I need planning permission for an extension?: Many single-storey rear extensions fall under permitted development, but the thresholds depend on your property type, its planning history and whether you are in a conservation area. We establish this at survey stage and tell you plainly which route applies before you commit to anything.
Can you work from my architect's drawings?: Yes. We price from existing drawings and structural calculations, and will flag any buildability issues before work starts rather than during. If you do not yet have drawings, we can introduce you to practices we work with regularly.
How long does a typical extension take?: A single-storey rear extension is commonly twelve to sixteen weeks on site once foundations begin, subject to size, ground conditions and inspection dates. Your programme is issued with the quotation, and you are told promptly if anything moves.
What happens if something unforeseen is found?: Unforeseen conditions — poor existing foundations, undocumented drainage, asbestos — are priced as a variation and agreed in writing before the work is done. Nothing is added to your bill without your sign-off first.

Also from MARL

The other two disciplines

02 / DECORATING

Decorating and specialist finishes

Preparation-led interior and exterior decorating, plastering and specialist coatings — the trades where the standard of the finish is decided long before the topcoat.

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03 / MAINTENANCE

Property maintenance and repairs

Reactive repairs and planned maintenance for landlords, managing agents and commercial premises — with response times, records and one number to call.