Exploring New Home Construction

Instructions To Help You Roof Your Home Using Two Types Of Modified Bitumen Roofing Materials

When your flat or low-slope roof is in need of replacement, modified bitumen roofing materials are a good option for DIY roof repairs. They can be easy to install and can last from six to twelve years. And the highest average cost to re-roof a 1,200 square foot roof with modified bitumen is $750.00. Here are instructions to help you re-roof your house using two types of modified bitumen roofing materials.

Peel-and-Stick Modified Bitumen Roof

Before you can replace your flat or low-slope roof with new roofing materials, it is best to remove all the old shingles and roofing layers. When you apply new roofing materials over your existing roof, it can cause the new roof to look lumpy and uneven. It can also cause your new roof to not last as long and will add unnecessary weight to your home's roof, which can cause damage to your roofing structure. 

A peel-and-stick modified bitumen roof is one type of flat and low-sloped roofing material that you can install by yourself. First, cover your roof decking with a layer of roofing felt by rolling it across the length of your roof. Cut off the felt even with the edge of your roof.

Attach the roofing felt with cap nails set every five inches along both sides of the felt roofing, then a row of nails down the center of the felt to hold it in place. Install the drip edge flashing over the felt at the edges of the roof, using cap nails. If any water gets under the shingles at the edge of the roof, the flashing will prevent it from seeping onto the felt underlayment.

Roll out the bitumen and cut it to fit your roof with an extra 1/2 inch over the flashing. Remove the adhesive backing from the roll and lay it flat over your roof. Repeat this process for each roll application. Overlap the lengths of bitumen by six inches as you lay them. Then, press the bitumen flat, especially the ends using a weighted roofing roller. Finally, use roofing cement to seal all the edges and seams of the bitumen layer, then press down once more with the weighted roller.

Torch-Down Modified Bitumen Roof

A second type of flat and low-slope roofing you can install is a bitumen roof applied with heat from a propane torch. Because you are using a propane torch, be careful you don't start a fire or burn yourself. Apply the felt underlayment using the same process used for the peel-and-stick bitumen roof.

After your roof has been covered with felt underlayment, roll out a layer of bitumen roofing and measure it to the width of the roof. Cut off either side of the bitumen to hang past the flashing by 1/2 inch. Then, roll up the bitumen halfway into the roof as you will heat and roll the roofing material one-half at a time. 

Make sure to wear gloves, heavy-duty boots, and long sleeves when you do this next step of the process to protect yourself from burns. Use a propane torch and heat the section of bitumen roll nearest the roofing felt until the roll starts to bubble. With your foot push the roll over and press it into the roofing so the melted section sticks to the roofing felt. 

Repeat this process until you have heated and applied one half of the bitumen roll. Roll up the other half of the bitumen and repeat the process of torch-heating and rolling the material over the roof. When you apply the next length of roofing bitumen, make sure to overlap each layer by a few inches. Press down the seam between each length of bitumen to make sure they adhere complete to one another to make the roof well-sealed.

These instructions can help you install your roof with modified bitumen roofing.


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