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Flat Roof Terrace

Wondering whether to convert your flat roof and create a relaxing terrace space?

In this modern age where living space can feel limited and overcrowded, converting your flat roof into a terrace space can not only create an inviting, luxurious outdoor area. But also add value to your property.

In this blog we explore the process you need to go through before work on building your terrace can begin, as well as outlining the construction process of building a flat rood terrace.

The First Step To Creating A Flat Roof Terrace

Initially the most important thing to do is to seek professional guidance as to whether your current roof has the capability of being transformed into a flat roof terrace. A specialist will need to evaluate whether your current roof is able to withstand the weight of the furnishing and fittings, as well as the additional weight of the people who will be enjoying the area and the constant footfall.

After the specialist has confirmed that your current roof has the ability to be used as a terrace, they will then sit down and discuss with you the level and manner of construction work that needs to take place.

Will I Need Planning Permission?

That depends on the amount of work needed, if the specialist advises that it needs major construction work then yes, you will need to have planning permission granted. That being said, the process of building a flat roof terrace is considerably easier than that of other flat roofing systems, so it is unlikely that your flat roof terrace will be deemed to need planning permission.

Inform Your Neighbours Of Your Plans For A Flat Roof Terrace

As with any sort of construction work on your property, it is always a good idea to have a conversation with your neighbours about the work you want to have done as this will give you a good platform to gauge how supportive of your project they are. Having that conversation with your neighbours also gives you the opportunity to address any concerns they may have rather than them going to the council to object against your project and creating any unnecessary disagreements. Should they seem unhappy it is advisable to try and come to a written agreement before contacting your architect to draw up plans for your flat roof terrace.

The Planning Process For A Flat Roof Terrace

Now that you have ensured you have the support of your neighbours the next step is to contact an architect who will be able to confirm whether or not planning permission is required. Local architects1 are the best to contact in this instance as they will be up to date and aware of your council’s current restrictions and process for obtaining permission. It is essential that you speak to an architect before booking in or having any flat roof terrace system installed. If the council deem that you should have sought planning permission after your terrace is built they do have the power to order that your flat roof terrace is removed.

What Are The Best Waterproofing Systems For A Flat Roof Terrace?

A flat roof terrace can be waterproofed in a number of systems including liquid, asphalt and GRP.

A liquid roofing system is the amongst the leading options for waterproofing a flat roof terrace. It is a cold applied process, which simply means that during the installation no open flames are used. One of the great benefits of using a liquid system is that it leaves a fantastic seamless finish and can be easily moulded around any complex detailing such a rain water outlets or soil vent pipes2. This makes a liquid system stand out against more traditional systems such as felt. Liquid roofing systems also come with great guarantees of up to 25 years.

The Process Of Waterproofing A Terrace With A Liquid System

• Firstly, a primer will need to be applied to the foundation of the construction point. Before any liquid waterproofing starts the joints in your substrate will be covered with self-adhesive tape.

• Next, each corner of your flat roof terrace has a liquid waterproofing coat applied to it, followed by a reinforced fleece membrane being cut down to the correct size and placed in each corner.

• After these steps have happened another layer of liquid waterproofing is applied, followed by an additional piece of reinforced fleece membrane (with a 175mm width and a height of 75mm) being placed in the upstand.

• It is now time for the fleece membrane to be embedded into the coating and for a layer of liquid waterproofing to be applied so that it covers all areas of the fabric – including any folds.

• Rainwater outlets3 will be identified and a length of reinforced fleece membrane (that is 50mm longer that the outlet’s circumference) will be cut out for them. Workers will then make cuts that are 20-30mm apart along the length of the fleece membrane.

• A base coat of waterproof liquid will be put around the water outlets diameter and the previously cut fleece membrane is inserted into the rainwater outlet hole. Next workers spread the small cuts around the diameter and apply more liquid waterproofing to all areas- this is because we need to make sure the fabric is embedded with the liquid water proofing coat.

• Now attention is turned to the outside of the rainwater outlet- a square of fleece membrane with a circle in the centre and a star cut for the rainwater outlet hole is placed over the outlet with the star cuts pushed out and down into the rainwater outlet.

• This process is then repeated for the pipe penetrations - the fleece membrane is 50 mm wider than the pipes circumference and once again cuts are made which are 20-30mm apart. The section of the fabric without cuts is 150 mm and this is because the pipe will end up 150mm above the roof level.

• Now a base coat is applied around the section of pipe that is protruding and the preciously got 150mm membrane is added. The solid section of the membrane goes onto the pipe and then the area with the small cuts are spread out around the section where the pipe meets the flat rood terrace. Once again, the liquid waterproofing coat will be applied to the fleece membrane- with careful care taken to ensure it is all embedded.

• Next, a second piece of fabric is cut to make a square and put over the pipe with a circle drawn around its circumference and cut out. By cutting the circle out it ensures that the fleece fits snuggly around the pipe. Once more a base coat is applied on the first piece of fabric, then the second piece of fabric is added and embedded into the coating. To finish, a top coat is applied across the whole area around the pipe.

• Finally, it’s time to apply an initial layer of liquid waterproofing to the remainder of the roof’s surface. Workers will now roll out the polyester fleece membrane and add the top coat to complete the system.

• Sometimes an anti-skid layer is then applied once the liquid roofing system has been completed. Should this be something you wish to be added it has to happen once the liquid roofing system has cured. Workers will tape out the area that is receiving the anti-skid layer (generally this is the perimeter of the roof).

• Once this has happened another layer of liquid coating is put down, followed by a generous amount of coloured quarts being spread across the wet coating, which workers will continue to scatter until there are no visible wet patches.

• The terrace area is then left to dry for 2-3 hours and workers will sweep the surface to remove any remaining quartz. Next a coat of milky white resin is applied on top of the quartz, this resin becomes transparent when dry.  Finally, your flat roof terrace is complete and ready for you to enjoy.

If you would like any further information or a quote for the construction of a flat roof terrace please do not hesitate to get in touch with us on 01277 375 511. One of our friendly team will be happy to help you.