1. Remove the Existing Roof

Firstly, you have to remove the existing roof to prepare for the installation of the new roof. Even if you only need to install new underlayment and flashing, then you must remove the existing roof first.

When you take off the exterior layers, make sure that you either pound flat or remove any nails that you come across. You do not want nails to rip into the new shingles that you are about to install.

Also, since the existing roof removal will, of course, lead to a lot of waste and debris, it is important to put down a tarp near your building to catch any waste or debris. You could set up a waste bin near your work area too.

2. Install the Underlayment

By now, you should have a totally debris-free roof. If not, then you can always use an air compressor to clean the surface.

The next step is to put a self-adhesive underlayment on the bare roof sheathing. This underlayment must be completely waterproof since it will act as a barricade against rain, wind, and snow.

Some building codes now require a specific amount of underlayment to be applied. Also, there are rules for how much of the roof the underlayment must cover.

Since underlayment clings well to a building structure, you might notice that some of the original underlayment still lingers. If you can not fully get rid of all of it, then simply make sure that the roof surface is as level as it can possibly be.

3. Cover Underlayment with Tar Paper

The next step is to add a second protective layer to the top of the underlayment. You must use No. 13 or No. 15 felt paper, also known as “tar paper”, which can be bought at any home improvement store.

This felt has been specially treated with an asphalt-composition or asphalt mix to make it impervious to water. As you go higher up on the roof, make sure you overlap each consecutive layer by about two inches.

The overlapping will boost the water-resistant properties of your roof. also, this will make it less likely that heavy winds will be able to force water to go in between layers.

4. Add the Flashing

To make your new roof appear as aesthetically pleasing as possible, make sure to install drip edge flashing beside the eaves.

Simply nail the flashing down to hold it in place. This drip edge will keep any materials from rolling over the edge and will give your roof a decent, finished look.

Also, you can flash the valleys of your roof because this is where water usually pools after heavy rain or significant snowfall. Also, you need to add flashing to any structures that protrude from your roof such as vents or chimneys.

The flashing will also give your roof additional reinforcement and protection from the rain. Every opening, crease, and corner needs to be taken care of. Your roof is only as effective as the weakest part of your roof. This is why paying attention to every detail is critical.

5. Lay Down the Starter Shingles

Roofing experts commonly refer to the first shingles laid on a roof as the “starter shingles.” It is critical to get the “starter shingle” placement and adjustment correct since they are the basis for the new rows that you will be laying down.

Using chalk lines can help guide you and is recommended by many experts. You need to find the center of the roof near the top. From the center, begin a chalk line.

You will then work right and left (or left and right with certain roof types) of the chalk line in a regular pattern while using the chalk line as your guide.

6. Install the Shingles


Next, you will need to lay down the exterior layer of the roof of your home or commercial building. If you have not already laid down the exterior layer, then you must transfer the heavy bags of roofing supplies to the roof.

As you get ready to put down the very first row, you can easily rip off the tabs from the three-tab shapes and connect them with their adhesive, self-sealing layer. The strips should be facing upward alongside the eaves.

The majority of roofing experts will tell you that the first row should have a slight overhang with the drip edge. This overhang should be no bigger than a fourth of an inch beyond the drip edge.

Also, remember the overlapping principle which says that as you work your way along the roof, you should make sure that each new layer slightly overlaps the layer before it.

7. Nail Down the Layers

Roofs should have maximum protection from rain and wind. This means that you will have to ensure that your roof materials are tightened securely to the roof’s surface.

The way to do this is to simply nail the shingles and flush with the starter ones. The decision of how many nails you use for each shingle is completely up to you.

However, the typical number is four nails for every shingle. In some unusually gusty or high wind areas, you may want to use as many as six nails.

You can use horizontal chalk lines up the roof if you need help getting the orientation correct. You can certainly ensure that you are laying down perfectly straight rows with chalk lines.

8. Install Additional Flashing If Necessary


You can never be too careful when it comes to working on a new roof. You certainly need to ensure that each architectural flourish or structure has been properly accounted for. This is when you must apply dormer flashing to a roof.

The dormer is the whole structure that protrudes from a building that includes a window. You will also need to do a quick inspection of the rooftop to find all of the stacks. Anything that protrudes out will need to be covered up with protective flashing.

9. Cap the Ridge


The ridge is found at the very top of a roof. On a traditional building, the ridge is easily found.

It is where the two sloping sides of the roof come together. It is critical to cap the ridge to give the roof extra protection.

This step is often overlooked. However, an exactly straight ridge cap is crucial to the entire protection of a roof.

10. Seal Up Any Exposed Nails and Remove Debris

The final step is the step where you clean-up and take care of all the finishing touches. For example, you may discover that some nails are protruding from the roof.

Make sure that you hammer everything flat and seal up exposed nails. You should also consider sealing up exposed flashing as well.

It is most likely the case that you will also have a small amount of waste and debris from all of your hard work. This is why you should cart away all of your materials.

If you have a waste bucket near you, then it might be easier to directly deposit the waste into the bucket rather than fret about carrying the waste down a ladder.

Roofing Safety Precautions

It is important to know that any time you are working on a roof, you should take extended safety precautions for yourself and for anyone else on the ground as well.

Dangerous roof falls are more prevalent than you think, particularly if you are hauling heavy materials down and up a ladder. That is why many people recommend utilizing a full fall protection kit.

Furthermore, because you are working outside, there is always the risk that you could fall off a roof due to unexpectedly slick surface areas on your roof. The type of shoes you wear is very important since they provide you with plenty of traction on a roof’s surface.

Final Words

Properly roofing a building yourself can save you thousands of dollars. It can also be a lucrative skill to learn.

Roofing a building can become a full weekend DIY project easily. This is especially true if you are trying to install a roof on a building that is relatively large in size.

Understanding the importance of the materials needed to roof a building, the tools needed to roof a building, and roofing safety precautions will help you achieve your roofing goals faster.