Install flat roofing

Pro Tip: even though many roofing and home improvement websites list modified bitumen, tar and gravel and liquid roof coatings as viable flat roofing materials, we personally would not recommend any of these to a homeowner.

Each of these has too many potential problems, they are difficult to install correctly, as well as costly and challenging to repair.

In short, they are just not worth the trouble, given the abundance of better alternatives. Roof coatings manufactured for existing roofs and used to extend their service life by years. They are typically installed on top of single ply, modified or low slope metal roofs. For example, silicone coating is one of the most expensive materials you can install — Complex installation process that requires a lot of technical knowledge. Should only be done by and experienced pro.

While it may come as a surprise there are actually many metal flat roofs out there. Standing seam roofs or corrugated metal panels are the two popular profiles to install on a flat roof. While metal will be the most expensive out of all flat roof materials, its well worth the investment considering that it will last at least twice as long as most other options, and will require zero maintenance. Most popular metals that are installed on flat roofs are aluminum or steel.

Aluminum is a more expensive and durable option compared to steel. If you are choosing among steel sheets, go for thicker metal, such as galvalume, as it will offer better protection.

Keep in mind that if you choose cheaper corrugated steel panels with fasteners, you may have to deal with rust and leaks that may happen around the fasteners. However, even this type of metal flat roof will last much longer than singly ply membranes, spray on coatings, or modified bitumen roofs. In terms of style, a flat metal roof will look best on a contemporary house or over a three-season porch, garage, or a modern house addition.

We will cover in extensive detail the most common problems that impact the durability of a flat roof. The biggest problem for most flat roofs is the presence of seams and flashing, because that is precisely where leaks occur.

PVC and TPO are the only two membranes that have hot-welded seams that will never come apart, and therefore do not allow any moisture to penetrate. Tar and gravel, modified bitumen and rolled asphalt offer extremely poor protection against leaks and ponding water.

EPDM rubber typically fails at roof penetrations, flashing and seams, allowing moisture to penetrate. One of the biggest issues with spray-on roofs is that the insulation can be eaten by birds, therefore also resulting in leaks.

Built-up roofs are typically 0. Single plies and spray foam roofs are generally easy to puncture by direct contact with a sharp object. Some PVC materials come with a fiberglass reinforcing scrim, which makes it very difficult to puncture. Keep in mind that increasing the width of a single ply membrane DOES NOT improve its ability to protect against leaks, However, it can extend its overall life, and makes it more puncture resistant.

Today, PVC roofing is considered the most durable. It is especially formulated to remain intact in a wide variety of adverse weather conditions rain, snow, wind, sun, hot and cold temperature fluctuations. Moreover, what makes PVC so strong is the fact that the top and bottom ply of the membrane have almost equal thickness. To compare, TPO roofing has questionable durability, as there is no consistent formula among manufacturers, who are experimenting to make it as durable, but also cheaper than PVC.

As with any product, we all know what happens when you try to slash prices by lowering the quality of materials. Your email address will not be published. Interesting debate. We inspect regularly and seams are still perfect. Advice I can add to the conversation: Build where you can minimize debris, tree branches, squirrel activity. We have zero of those problems on our site. Definitely get a good installer. Tapering the insulation board under the membrane was a pain in the body part, according to my contractor but it was key to ensuring no pooling.

Watch for pooling during installation and make sure it gets fixed. No rooftop gardening, stargazing parties, etc. For what it is worth: I have been involved in commercial roofing for over 35 years and have spent most of that time inspecting roofs of various ages.

In my experience the two best systems for longevity, resilience and ease of maintenance are: 1 4 ply BUR with 2 ply SBS flashings and gravel surface. The number of false welds found in year old thermoplastic roofs is significant. TPO manufacturers are still trying to figure out how to make the sheet both UV and fire resistant. First, thank you for this very informative forum. I need to replace a built-up roof on a sq foot mid-century house near a wildfire area in Los Angeles with a non-combustible roof.

After replacing any rotted decking, I am consider the benefits of adding DensDeck or some other non-combustible material. I am also weighing a silicone spray-on roof warranted for 50 years vs. Would welcome feed-back. Leo B? Carlos O? From reading your article you seem quite bias towards PVC. Mod-bit roofs are routinely being installed on buildings with the most sensitive, costly materials in the country where leaks are not tolerable. Redundancy in roofing is still king. Have an experienced professional specify the correct high quality material, add slope where possible, and hire an experienced company.

No matter the family of material this combination will produce a great roof. Recently purchased a property with an addition. It was obvious after having a look into a small leak we noticed in the corner of the room that the membrane was installed improperly. This led to a series of very expensive repairs. Just for a regular flat roof for edpm — should I go with 45 or 60 mils and what should thickness of insulation be. My attic is insulated between the rafters — does that matter?

For EPDM, you should go with 60 mil. As for insulation thickness, it depends on how much you can afford. Recommended roof insulation R-Value is R, but ideal is to have R or more. You want to have a total r-value of approximately Most likely the attic has r or r Depending on the size of the roof, the joists are placed a specified distance apart to minimize the weight-bearing load on any of them.

You can often consult an online chart to find the optimal distance based on the width and span of the roof. Generally speaking, the bigger the roof, the more joists you will need to hold up the roof.

You want enough to protect the structure, but not too much weight. You will also need a frame for a slight incline. This frame is important. The next step is to think about weatherproofing and waterproofing the boards that are laid across the joists. The classic option is EPDM rubber or a combination of rubber with felt or fiberglass.

This is used to cover the boards and make them waterproof. With some sealant , you can create a very safe covering. You can find more details in a flat roof construction manual. In order to make the roof as stable and strong as possible, you will also want to give some thought as to how the decking and the joists will fit together. Below is an easy-to-follow manual for building flat roofs, including a guide to flat roof framing and installation with plenty of details and specifications about the frame.

If you want a DIY flat roof, here are the steps to follow. That would be impossible, since a flat roof would receive so much weight from water buildup and snow buildup that it would not be long-lasting.

Some roofs actually slope in several directions, ensuring optimal water runoff. This will help you create a flat roof framing plan. When framing a flat roof, you will need to create a slight incline. You can do this with a foam layer that exactly fits your roof. For very small roof jobs, you can achieve the same effect by taking 2x4s and converting them into long wedges that you can then nail to the joists.

These will be larger and closer together than on a pitched roof in order to handle any snow or water. You must now create a soft, protective base for the rubber. You can cut this IsoBoard easily with a knife. Once you have the right size, you can secure it to the plywood sheathing with screws and steel washers. You will want to make sure that all the pieces fit snugly against each other.

This is important for the installation. The answer to this question ultimately depends on what kind of a flat roof you have. Different materials have various life spans. Here is what you can expect:. Based on my experience in this field for the past 15 years, rubber is the least durable membrane, that last years, at best. This is under perfect conditions.

PVC — this is the longest lasting single ply membrane, with service life of years, or more. Modified Bitumen — this is another short lived material, with life expectancy of about years. Rolled Asphalt — it is almost never installed today, and for good reason. It only lasts years. Therefore, depending on what you have and how many years passed since it has been installed, you have a pretty accurate sense of when it will be time to replace it.

Its important to realize that many of these materials fail completely and require replacement long before these projected average life spans. This usually happens as a result of sub-par installation, or if the house is located in a particularly harsh climate. If you are planning to install a flat roof, it is very important to put in high-quality insulation , with appropriate R-value.

Without it, you will be wasting a lot of money on heating and cooling costs. You will also experience severe temperature fluctuations inside your house. The best product out there is Polyiso rigid foam. It is available in various thicknesses, at 1 inch increments. We recommend you consult with your contractor to figure out what type of insulation will work best for your home, and how much of it you will need.

Pro Tip: It is not a good idea to save money on insulation. It will only result in decreased service life of your roof, poor energy efficiency, as well as uncomfortable temperatures inside your home. Most likely, you will end up spending more money to fix insulation problems, which could have been avoided from the beginning.

To determine whether its best to do hire a pro to fix your leaking roof or install a new membrane ask a professional contractor to conduct an inspection. Make sure that you hire a pro because a general contractor or a residential shingles guy will not know all the nitty-gritty details and complexities of flat roof materials. Therefore, he may give you wrong advice that will cost more money and time to fix down the line. It is very important that he does a test-cut cut through the material to see what is under the top layer.

Very often, there is mold and rotted sheathing underneath, that is no visible on the surface. Whether you have just replaced or repaired your flat roof, regular maintenance is the key to its longevity. Even the best, most expensive products will not achieve optimal performance without proper care.

It only takes a few easy steps:. One of the greatest advantages of a flat roof system is that it can be highly energy efficient. This means that one of these membranes can help you save hundreds of dollars on your energy bills. Both are Energy Star Rated for their cool properties. It is important to note that white color roofs collect a lot of dirt and dust over their lifetime. Over time, this decreases their energy efficiency.

However, they still remain highly reflective. Good, regular maintenance can help prolong optimal energy efficiency of a white membrane. Today, many darker color membranes are are also formulated to have light-reflective properties and offer energy savings. In fact, because they are so dark, they can heat up to degrees in the summer, making your HVAC system run over-time and rake up huge energy bills. At the end of their service lives, old membranes get recycled back into making new ones.

It is possible to install a PVC membrane over an old roof, thus eliminating tear off, which cuts your costs and saves landfill space. They all cannot be recycled, because they are made from petroleum based by-products. Therefore, they have to be landfilled. In addition to serving as a beautiful and durable cover for the house, a flat roof has a number of other useful applications. Many homeowners prefer to install a flat roof over a porch, a house addition or a garage.

One of the biggest architectural trends is to have a house with a sloped roof and build a modern looking addition with a flat roof. Moreover, a flat roof membrane can even be used to build a deck! If you are building a brand new home or an addition, remember that your flat roof will not actually be flat. Because a flat roof tends to collect water and sheds it much slower than a pitched roof, it may not be an ideal option if you live in an area that gets a lot of heavy rains and snow storms.