Property types
Fitting a shower room in a garage annexe
The short answer
A detached garage converted into an annexe or home office needs its own supply and waste connection run out from the main house, usually underground across a garden or driveway. The existing garage slab rarely has damp-proofing or insulation suited to a wet room, so the floor build-up needs addressing before any shower position is fixed.
Questions we get asked
How far can waste run from a garage annexe to the house drainage?
It depends on available fall; where gravity is not achievable over the distance, a small pumped waste unit is a practical alternative.
Does a garage shower room need building regulations approval?
Converting a garage to habitable use, including adding plumbing, generally falls under building regulations, so this should be confirmed with building control before work starts.
Where these jobs differ
- 1
An underground supply and waste run from the house needs to be laid at the correct depth to avoid frost, and access points should be planned in before the ground is reinstated.
- 2
The garage slab typically needs a damp-proof membrane and insulation added before any shower tray or wet floor is formed, since garages are rarely built to habitable-room standards.
- 3
Ventilation is easy to overlook in a converted garage shower room, and a ducted extractor is essential given the enclosed nature of most garage structures.
Connected pages on this site
Not sure which option suits your property?
Most of these decisions come down to what is behind the wall and under the floor. A site visit settles it quickly.