How to Prepare a Flat Roof for Liquid EPDM Application

What’s in this guide?

In this guide, we are going to look at the preparation of a flat roof for liquid EPDM waterproofing application. Preparation of the area is critical to ensure a successful application of the Permaroof100 Liquid EPDM system.

Failure to prepare the surface properly can potentially lead to compromised performance of the finished project.

Preparation is the most important step in all flat roof projects.

Preparation of the flat roof must be carried out before opening and mixing the product, as once combined with the accelerator, the Permaroof100 Liquid EPDM has a pot life of 25 minutes.

Before you begin, read the following considerations:

Tools you will need

For the most part, there are no specialist tools required for the preparation of the surface area. You will need a few basic items, most of which you should already have in your store cupboard or garden shed:

  • A domestic garden broom – hard to medium bristles
  • A dustpan and brush
  • Ordinary detergent
  • Oil or grease remover
  • Pressure washer – optional for the removal of tough grease patches
  • Masking tape and paper or self-adhesive strips
  • Tool for scraping out cracks to remove dirt or vegetation.

Roof surface type

The level of preparation will depend on what type of roof surface you are covering. Permaroof100 liquid EPDM waterproofing systems are suitable to use to cover a range of materials:

  • Asphalt felt
  • EPDM membrane
  • Other single-ply membranes
  • Cured concrete roofing
  • Metal roofing systems
  • Wood
  • Asbestos encapsulation
  • And more.

Permaroof100 liquid EPDM will cover wood, but only if it is good condition.

You will waste your time and the product attempting to cover damp, rotted or otherwise damaged wood.

If you have damaged wood present within your coverage area, this will need to be dried, repaired or replaced before application. Remove or knock in proud nails or screws.

A consideration for concrete roofing is that it needs to be cured and fully dry before applying the product. If you attempt to cover green concrete (concrete that is newly-poured or wet), the product will not perform, and the integrity of the concrete will be compromised. The average curing time for green concrete is approximately three weeks, but this will also be dependent on your geographical location and climate.

Now let’s look at the steps you need to take to prepare the average flat roof for application of Permaroof100 liquid EPDM.

Step one

First use a domestic brush or yard broom to completely clear away any loose surface dirt, stones and other debris, making sure that the area to be treated is completely clear.

Ensure that there is no moss or other vegetation growing within the coverage area. Remove it completely if it is present. Scrape out any cracks and clear them of dirt or vegetation if necessary.

Step two

Check the entire surface area of the flat roof. Remove any grease or surface dirt patches by washing down with a suitable cleaner or ordinary warm, soapy water. If this does not remove the grease or oil, then use a pressure washer or a suitable degreasing solution to ensure it is removed.

Step three

Check the flat roof surface area for any loose existing material. If you are covering a felt roof, cut away or glue down and loose flaps of felt. Remove or secure loose or broken concrete during this stage of preparation too.

Step four

Brush the surface area again with the domestic brush and remove any debris using the dustpan and brush.

Step five

Allow to dry thoroughly. This is a critical step that cannot be overlooked, however tempting it may be to continue with the project. Once fully dry, briefly check the coverage area again and brush once more with the domestic broom to make sure any surface dirt and dust is removed, and you have a clear, clean and dry surface area to work on. Now, you are ready to begin mixing the product.