How to Replace a Flat Roof

When your roof is leaking it should be fixed as quickly as possible to prevent further damage from occurring. If left unevaluated for too long, severe damage can be caused to the foundation or internal structure of your roof which will lead to a higher cost in repairs or in some cases, an entirely new roof.

Of course there are many different types of roofing however, in this post we will be focusing on how to replace flat roofing. The following guidelines should help you easily identify the materials and procedures to get the job done as quickly and easily as possible.

Step 1. Decide on a type of roofing

Before beginning though, you will need to decide which type of flat roofing you prefer to install. Each come in the form of a roll that measures 1 yard or by 1 meter. All types will need a periodic inspection to check for punctures, cracks, or any other forms of damage. Each roofing roll falls into the following categories:

  1. Sprayed Polyurethane Foam – Applied by spraying or squeeging onto the roof surface
  2. Modified Bitumen (aka Asphalt) – A single layer of asphalt treated & granule coated felt is either hot sealed or cold cement sealed to a base sheet or primed decking
  3. Built-Up Roofing – Treated felt that uses hot tar or asphalt overlaps the roofing surface, but can crack easier over the years
  4. Self-Adhesive Rolls – A single layer is applied, aligned, and then smoothed down

Step 2. Determine what kind of materials you are going to need

Different types of roofs will require different types of tools and materials, so make sure you are using the appropriate ones for each type

Step 3. Start removing the old roofing

Using a shovel or other special roofing scraper, start loosening and removing any presiding roofing

Step 4. Check for areas that have dry-rotted or have endured water damage

Check out all areas of your roofing for damage. These areas won’t drain well and as mentioned earlier, can only lead to further damage such as standing water.

Some roofs are equipped with drains and now is a good time to make sure that yours isn’t clogged if you have one.

Step 5.  Lay out the base sheet or felt paper

Not all roofing types will require this process but for those that do, this is how you do it. This base sheet is typically made of polyester, paper, or fiberglass that is saturated with asphalt. You are going to want to over lap these with a 2-4 (5-10 cm) difference between sheets.

To pin them down, you will need some large roofing nails that are thin headed. Fasten down the sheets using your roofing nails spacing them about 8 inches apart along the overlapped edges, and 12 inches staggered.

You are also going to need to cut your roofing material to fit around the type of vent on the roof of your home.

Step 5. Top it off using flashing

Flashing will help prevent your vents and other areas from water and other external damage. Plastic roofing cement can also work great for this.