Garage Conversion Project Plan – Week-by-Week Timeline for Brighton & Hove

Follow a proven, six-week build programme that keeps Building Control and budgets on track.

Overview of the Conversion Timeline

A single garage in Brighton typically needs four to six on-site weeks once legal permissions are in hand. Coastal weather, bungaroosh remediation and inspector availability can add a few days, but the outline below covers every milestone in the most efficient order. Adjust the pace for larger or listed garages—yet keep the sequence to avoid costly re-work.

Pre-start Essentials (done before Week 1)

Secure your Lawful Development Certificate or planning approval.
Sign off structural calculations for the steel or glulam goal-post.
Book Building Control and agree inspection dates.
Order long-lead items: steel beams, roof lights, bespoke windows, MVHR kit.
Clear the garage of belongings and isolate redundant electrics.

Week One – Structural Preparation

Remove the garage door and frame.
Prop the opening, then install the goal-post uprights and top beam.
Cast padstones or bolt spreader plates to the existing slab.
Pour any mini-pads if the slab is too thin for point loads.
Build dwarf walls or install temporary stud infill to secure the shell overnight.
First Building Control visit: inspect beams and padstones.

Week Two – Shell, Damp Proofing and Floor

Build the cavity infill wall or glazed screen.
Chase out wall chases for electrics and plumbing.
Lay 1200 g DPM lapped up walls; tape joints.
Install perimeter insulation up-stands.
Fit 100 mm PIR (or mineral wool plus lime screed for bungaroosh) and pour 65 mm screed.
Photograph hidden layers for the inspector if rain delays the visit.

Week Three – First-Fix Services and Roof

Run new ring main on RCBO from consumer unit; clip cables in safe zones.
Pull CAT-6 data and coax to desk or media wall positions.
Lay plumbing feeds for radiators or under-floor heating mat.
Install ventilation duct runs or MVHR unit.
Upgrade flat roof insulation: 120 mm PIR over deck, vapour barrier, single-ply membrane.
Fit roof lights or lanterns, flashed in marine-grade aluminium.

Week Four – Insulation, Airtightness and Plasterboard

Batten walls at 400 mm centres; infill with PIR or mineral wool.
Staple a continuous vapour-control layer; tape every penetration.
Add 37 mm insulated plasterboard and screw fix.
Fire-tape ceiling joints, forming a 30-minute barrier under rooms above.
Offer Building Control a pre-plaster inspection for insulation sign-off.

Week Five – Second Fix and Internal Finishes

Install radiators or commission the UFH mat.
Fit switches, sockets, data plates and down-lights.
Seal window reveals with airtight tape and return insulation 20 mm onto frames.
Skim plaster walls and ceiling; allow three days to dry with dehumidifiers.
Prime and first-coat breathable emulsion or clay paint on bungaroosh backing walls.

Week Six – Flooring, Joinery and Snagging

Lay engineered-oak boards, acoustic underlay or rubber gym tiles.
Fix skirting, architraves and internal doors.
Touch-up paintwork after trades complete.
Balance MVHR airflow or set humidity-sensor extractor.
Final Building Control inspection: present structural, electrical and ventilation certificates.
Clean site, photograph finishes and issue the ten-year workmanship warranty.

Post-completion After-Care

Maintain background ventilation for at least three months while residual moisture leaves the new screed.
Check surface humidity with a cheap digital meter; aim for 50–60 percent.
Limewash or silicate-paint any external lime render every five to seven years.
Re-seal external doors and windows annually against salty sea air.

Common Timeline Delays and How to Avoid Them

Rain hitting screed pour day → book a tented scaffold or reschedule for morning when Brighton averages lower humidity.
Late steel delivery → order beams at least two weeks before site start.
Bungaroosh blow-outs behind cement render → allow a contingency day for hot-lime patching.
Missing RCBO spaces → check consumer unit capacity during the pre-start electrical survey.