What you need to know before repurposing your rooftop

With the size of our residential acreage decreasing, many homeowners are keen to reclaim the rooftop space and repurpose it for a variety of uses.

However, repurposing a rooftop is much more complex than expected. There are many safety, functionality and design considerations to take into account before homeowners can undertake the project.

Nasser Sserunjogi, a civil engineer says rooftops can be used for several activities such as gardening, storage or entertaining space.

“So, the work needed to transform the space will depend on the activities it is being designed for,” he says.

However, there are some general elements that should be put into consideration before a rooftop can be repurposed and these include:

Physical load capacity

Sserunjogi says there are structural issues to be addressed before one repurposes a rooftop.  For instance are structural modifications necessary? Will there be new openings and penetrations? What is the impact of mechanical systems and will they force any structural modifications? 

Also find out whether the roof will be used for small groups or as an event space for larger numbers of people, as this will determine the infrastructure upgrades required. At a minimum, slab reinforcement will likely be required to support new paving and planting, as roofs are typically designed to a lower live load capacity than occupied spaces.

“Get an expert to inspect the structure and advise whether you may need support to accommodate the anticipated structural load,” he says. 

He notes, however, that it is advisable for property owners to include the possibility of using the rooftop for during the planning stages.

 “This way, the roof structure is not only in harmony with the overall design, but also emphasises the building’s style and character. It will also determine the materials used and structural modifications added,” he says.

If you want to turn your rooftop into a usable space to for instance to be able to hold multiple people or accommodate a garden, new buildings will need to be built more sturdily and existing buildings will need to be reinforced.  

Attractive accessibility

There are two types of rooftop accessibility the outdoor and indoor. The indoor one works better for in house members only, but if the rooftop is going to be used by other people the outdoor is ideal.

An outdoor access leading from the ground to the rooftop makes entertaining guests easier because they will not need to use the interior stairs of your home.

Before deciding which type to settle for consider different variables such as how often it will be used and by how many people. Will it need to support the weight of humans or heavy loads as well? Is your rooftop on an incline or is it level.  Will you need gates? Next, choose the materials suitable for differing types of access. 

There are products designed to avoid rust, corrosion and retain chemical resistance, while without interfering with the structural integrity of the roof. For easy and accessible connection between interior space and your rooftop space you can either use concrete steps or steel.

Railing

To make your rooftop safe and secure, install a railing. The railings should be at least 36 inches in height while the space between individual balusters should be less than four inches, and the space between the bottom of the railing and the top of the deck surface also should be no more than four inches.

Waterproofing

One of the biggest challenges when repurposing a rooftop is drainage and water proofing. 

“Normally rooftops are susceptible to some level of water retention or flooding, depending on the type. If this water is not drained, it can result in structural damage. The solution is to find ways of draining it or waterproofing the surface,” says Nasser Sserunjogi, a civil engineer.

It is also important to contact a roofing contractor to conduct a thorough roof inspection. That way, homeowners will have a better idea if the roof is in good condition and suitable for the project.

The rooftop may block the current flow of rainwater, for example, which means there may need to be additional access to drains and utilities. Replacing the roof entirely may be required to allow for more optimised measures to be put into place, such as a waterproof membrane between the shingles and the new structure.