Converting a garage? Tips to ensure council approval

With many adult kids moving back into the family home since the start of COVID-19 and people experiencing more time on their hands, it probably won’t surprise you to learn that there has been a huge spike in home renovations in Perth this year.

As much as it may be tempting to bypass the council approval process, it isn’t worth the risk. While the room may perfectly satisfy the intended purpose in your eyes, it may not be able to be classified as a room when you decide to sell without approval. Many vendors are unaware of this. While retrospective approval is possible in order for a sale to proceed, it’s not an easy process because certain functions carried out during the build may no longer be visible or easy to check by a building surveyor, such as waterproofing.

One part of the house that has become increasingly popular to renovate is the garage. Below is a ‘cheat sheet’ created by a building certifier containing 8 essential steps to ensure council approval of a garage conversion.

1. Waterproofing

If you intend to have a person/people inhabiting the space, it must have adequate waterproofing. This is the number one problem inspectors and buyers see if it is not done correctly. The easiest waterproofing method is to place a plastic waterproof membrane on top of the slab and then pour 86ml (1 course) of fresh concrete on top of it. The other method is to waterproof the walls (sometimes both methods are recommended). The wall can remain single skin, however it is not recommended as damp can occur. If the wall remains single skin, the external wall will require waterproofing.

2. Ceiling

This is another common mistake DIY renovators make – ceilings that are too low. For approval, the minimum ceiling height for habitation is 2.4m.

3. Smoke alarm

If the converted garage is to be used as a bedroom, a smoke alarm must be installed. This is not required if it is to be used for other purposes, such as a home office or gym.

4. Energy efficiency

The conversion must comply with energy efficiency requirements for a habitable room. You will need to obtain an energy efficiency report for approval. Click here for WA’s energy efficiency guidelines.

5. Light

When converting a garage, some people assume it is good enough to add artificial lighting. But to obtain council approval, there are minimum natural lighting requirements to meet. The opening to the room – a door or a window – must be at least 10% of the total floor area. If the door leads to an adjoining area, as is the case in many homes with internal access from an attached garage, the adjoining room has to meet minimum lighting requirements.

6. Ventilation

Again this relates to natural ventilation. To meet approval standards, at least 5% of the floor area must be a window or door that can be opened.

7. Fire

According to the building certifier, “The engineer will approve this requirement however it shouldn’t be necessary unless a window has been installed in an external wall”.

8. Certification

Ensure your plans are certified and you obtain all necessary approvals BEFORE converting your garage to avoid issues down the track.

Note: The floor doesn’t have to be level with the house and you don’t need a floor covering over the slab in order to obtain approval, as long as the slab has been waterproofed.

Before you start your garage conversion (in priority order):

1. Decide what the room will be used for.

2. Think carefully before sacrificing all secure, undercover parking space. If you intend to sell in the not-too-distant future, be aware that buyers today rate a garage more highly than extra living space.