Table of Contents Section 1: Most Common Types of Flat Roofing Section 2: Better Understand Your Flat Roof Section 3: Flat Roofing Cost in 2015: Four Factors that Dictate Section 4: Planning A Flat Roofing Project Section 5: A Roof Evaluation Form
Most Common Types of Flat Roofing Knowing what type of flat roofing material is on your building won t stop your leaks but it will help you make better decisions about maintenance, roof repair and or replacing an old flat roof system. Knowing more about your building s roof will also help you communicate and relate better to potential roofing contractors as you go through the interview process to see which roofing company is a fit for your project. Most common types of flat roofs 1. Bur or Build Up Roofs Bur or built up roofs have been in use for more that 100 year in the United States and are often referred to as tar and gravel roofs. Layers of roofing felt usually three feet wide were striped in and covered with melted hot tar. Workers would heat the asphalt tar or coal pitch to a liquid in a large kettle then mop it on the roof. After the2 2-4 plies or layers or roofing felt were mopped into place with the tar, the roofs were often covered in aggregate or pea gravel. The small stones or gravel was used to protect the tar from the damaging effects of the sun s UV rays. How to tell if you have a Built up roof Tar and gravel Look Small gravel is stuck in the tar Flashings around HVAC curbs and parapet wall are often covered in tar 2. Modified Bitumen Roofing Modified Bitumen is similar to a built up roof in that it is composed of asphalt rolls usually three foot wide but a mod bit roof is usually only made up of two plies or layers, a base sheet and a cap sheet. Modified bitumen can be installed four basic ways 1) hot applied with hot tar, 2) cold applied solvent based adhesive that
does not required the use of heat, 3) torched down with an open flame that melts the two sheets together, or 4) peel and stick base and cap sheets that self adhere once a release tape is removed. The cap sheet or top layer usually looks granulated similar to the granules on a shingle roof and is often light gray in color. How to tell if you have one. Seams in the roof every three feet. Granulated look to top layer resembles the granules on an asphalt shingle Note: Modified Bitumen roofs are sometimes coated with an elastomeric roof coating but you should still be able to see the seams or rolls in the roof and also the granules. 3. EPDM Rubber roof Rubber roofs are fairly easy to recognize and are installed in two basic ways 1) Ballasted or weighted down with large river stone, or 2) Adhered or glued down. Rubber roofs that are adhered are easy to spot, they are black in color and usually stretched tight over an insulation board or fiber board Rubber roofs that are ballasted are being held down and in place with the use of ballast or the large stones on top of the sheets of roofing. These roofs are covered in rock similar to a built up roof but the stones are usually larger and they are not stuck to the roof with tar. If you gently move stone away you will be able to expose the rubber membrane. How to tell if you have a rubber roof Rubber can easily be seen Rocks or stones can be moved to expose rubber membrane. You will also be able to see the rubber around the HVAC curbs, parapet walls and other flashings.
4. Spray Polyurethane Foam roof A spray foam roof begins with a layer of high density polyurethane foam sprayed from a wand or sprayer. The foam is then coated with some type of waterproofing elastomeric top coat. This top coat often reflective gray or white in color. How to tell if you have a spray foam roof A degraded top coat will expose the polyurethane foam Since the foam is sprayed on from a wand you can usually identify the spay pattern the applicator used during installed. 5. Thermoplastic membranes PVC or TPO Thermoplastic roofing membrane are single layers of material usually white or gray but can be found in other colors. Theses membranes can be either adhered, similar to a EPDM rubber roof, or mechanically attached with screws and plates. From a distance PVC and TPO membranes are hard to distinguish but will most often be white or light color. How to tell if you have a PVC or TPO roofing membrane Light color or white roof Tight look over building, looks like white rubber roofing These aren't the only types of flat roofing systems you ll find in but they are the most common.
Better Understand Your Flat Roof Knowing what type of flat roof the building has can help you make better decisions regarding the roof replacement and maintenance plan. 1. Roofing System. You should know what the existing roof system is, the age of the roof and if it is under a warranty. There are different warranties, ask the manufacturer what warranty you have, what is covers and the length of time; this will depend on the manufacturer of your roof material on what warranty you have, each manufacturer offers different warranties. The age of your roof matters too because there each roof system has a different life cycle or life span than another. This can also tell what condition the roof should be in based on its age and location. 2. Structure and deck material. Know the type of structure and roof deck material you have. There are three types of roof deck materials that are used: wood, concrete and metal. 3. How much insulation you have and the condition of it. Re-roofing projects are great times to upgrade the roofing insulation if it needs it. However wet insulation will have to be removed or attended to. Your next roofing project will be much quicker and with much less mess laying over the existing roof and minimize the buildings exposure to elements and can be done in a most weather conditions. Taking a core sample of the roof will tell you how much existing insulation you have and if it is wet or not. Rubber TPO/PVC Metal Built up roof (BUR) Wood Metal Concrete Tar & Gravel 1" 2" 3" 4" 5"
4. The drainage system. Flat roofs have gutters, drains, or scuppers for the draining system. Most flat roofs have water that runs to guttering, into rooftop drains or to a hole through the wall scupper in a collection bay. Drains Gutters Scuppers 5. Termination and Trim. Flat roofs will have a variety of edge detail and trim. However the most common termination will be termination bar, drip edge, full coping cap and metal edge trim. Termination Bar Drip Edge Coping Metal Edge Trim 6. The level of foot traffic. Does the roof have light, medium or heavy foot traffic? Light Medium Heavy
Flat Roofing Cost in 2015: Four Factors that Dictate These are the top 4 Factors that dictate the cost of a flat roofing project in 2015. By understanding what drives cost in flat roofing you can more accurately plan and budget for your next re-roofing project. 1. Tearing Off A Flat Roof Having a flat roof removed is one of the biggest drivers of cost to a roofing project in 2015. Tearing off a flat roofing can be 50% or more of the total cost of re-roofing a building. Tearing off a flat roof requires much more labor, larger crew sizes, more disposal cost, adds time to project completion date, and the flat roofing contractor needs clear weather before exposing the building. It s easy to see how a tear off quickly adds cost to a roofing project, it s much more work. For this reason many single ply roofing manufactures such as Duro-Last, Carlisle, and Sarnafil are designing PVC roofing membranes that are intended to lay over older roofing systems thus saving the building owner the cost and headache of a flat roof tear off. One of the major stipulations of doing a flat roof lay over is that the roofing insulation and / or deck not be saturated. Building owners who allow flat roofs to leak for extended periods of time are not only going to incur cost associated with a tear off when they finally do decided to re-roof, but will also endure the cost or replacing the wet insulation. Being proactive towards maintaining and replacing a building s flat roof can equal big savings. 2. Poly ISO Roofing Insulation Most building owners or project managers often miss calculate the cost that roofing insulation adds to a flat roofing project. In 2015, 1 Sq. Ft. of poly ISO roofing insulation 1 thick has an average cost of.41 cents. That means to reach most standard commercial building R-values of R-30, you will need at
least 5 inches of poly ISO board. 5 inches of ISO at.41 per Sq. Ft. equals an additional $2.05 per Sq. Ft. not even including the cost of installation, shipping, and material handling. This is another very large advantage of doing a membrane lay over of your existing roof if it is not saturated with moisture. The building owner can save the cost of new insulation by leaving the existing insulation in tact. 3. Metal Copings and Trims Another area that dictates cost on a project is metal coping and trims that can be used to dress up a building. Metal copings and trims not only seal the perimeter of a building and tops of parapet walls, they add curb appeal and design to a facility. Coping caps and metal trims cost much more than termination bar and caulking but they mean a long lasting, watertight seal while adding the aesthetics of a building. 4. Type of membrane The forth factor that will affect the price of a new flat roof in 2015 is the type, thickness, and warranty associated with the roofing membrane you select for your building. Most major roofing membrane manufactures have warranties that are 15 year, 20 year, or 25 year long in duration. As you increase the length of the warranty you must also increase the thickness of the membrane. For example, a.40 or.45 mil roofing membrane will generally give a 15 year NDL or no dollar limit warranty, where as a.50 mil or 60. membrane will come with a 20 year NDL. In most cases to achieve a 25 year warranty on a flat roof you will need to increase the membrane thickness to.80 mil.
Planning a Flat Roofing Project There is a lot that goes into planning a flat roofing project at your building or campus. Here is a list of things that will assist in the planning: 1. Material Delivery Commercial roofing materials are often delivered by a large flat bed truck and or semi and trailer. Pre-planning a route to and from the site as well as an off loading area can save time and avoid unwanted congestion or road blocks at your business or organization especially during your peak hours. 2. Staging and hoisting Most of the roofing material will be hoisted to the roof top either by crane or by an extended forklift. FI the material being off loaded will not be immediately set on the roof, try to be strategic when designating a staging area. Remember a crane should be able to reach the staged material and the top of roof. Resist the urge to set staged material under trees, power lines, or too far away from the roofing project. 3. Watch the wind Once materials are lifted to the roof take the extra time to secure rolls of roofing membrane, buckets of screws or glue, and bunks of insulation. The taller or more exposed the building is the stronger the wind will be. Plan on securing material accordingly.
4. Debris Handling Not every flat roofing project will involve a tear but for the ones that do, you will need to plan how debris will be lowered or thrown to the ground in a safe manner and how the debris will be removed from the job site, Be specific when speaking to you commercial roofing contractor and do not forget these important items: How will debris be removed from the site? Where will dumpster be set? Will trucks or equipment be allowed in grass or yards? How will landscaping be protected? How will the public be protected from falling debris? 5. Parking Arrangements If parking is limited at your facility, you will want to arrange a designated parking area for the roofing company s trucks and equipment. If parking is very limited ask your flat roofing contractor to in turn limit the amount of trucks they bring to the site at one time. 6. Establishing Working Hours/Days Set up reasonable working hours with your roofers keeping in mind that roofing isn t a job you can just walk away from after 8-10 hours of work. The job must be dried in each night before the crew can call it a day. Allow crews to work later when the weather is right and establish whether working weekends will be permitted or even required should the project fall behind schedule. 7. Power Supply
Determine with your roofing contractor what the power supply will be for the roofing project. Most flat roofing companies will have their own generators to run specialty equipment but they may also require additional outlets. Establish how cords will be ran / covered to avoid a trip hazard to the public. 8. Have you notified the tenants, staff or neighboring buildings? Letting people know ahead of time that you place to have a flat roof replaced and the approximate amount of time it will take will go along way in demonstrating your leadership ability, thoughtfulness and sense of team. 9. Do you have appropriate work permits, licenses, insurance and workers compensation? Check with your local building officials about required permits, fees or licenses you may need before roofing work begins. Make an up to date proof of insurance and workers compensation required as part of the bidding process and quickly eliminate any roofing company that is unable or unwilling to provide these documents to you. 10. Ensure your roofing contractor has a plan. Speak with your roofing company about their site specific safety plan and how they plan to maintain a safe environment for both the roofers doing the work and the public in and around the building. Ask for a copy of their safety plan and procedures should an injury or fall occur. It is also not a bad idea to have a copy of the MSDS sheets for the material being used.
DATE: LOCATION: INSPECTED BY: ITEM Debris on roof Drainage Physical Damage Attic Conditions Structural deformation ITEM Condition of coatings Granular Lost Punctures Cracks / Alligatoring Blisters / Fishmounths Ponding ITEM Roof Material Condition of Surface Deformed Edges Shingles: Buckled Metal: Curled EXTERIOR PRO INC. ROOF INSPECTION GENERAL ROOF CONDITIONS Missing Tabs Granular Loss Corrosion Fasteners FLAT / MEMBRANE SLOPED ROOF REMARKS REMARKS REMARKS Fascia Soffit Flashing ITEM Gutter/Drains. etc. Chimneys Skylights Control Zone Access Drains / Vents Cracks ITEM Water Staining Water Leaks Seasonal Change ITEM Deformed Finish Surface Deterioration Staining Cracks ITEM Water Staining Water Leaks SUMMARY/COMMENTS (Highlight areas of concern and any rapid degradation in roof system) ROOF FEATURES REMARKS CEILING CONDITIONS REMARKS EXTERIOR WALL SURFACES REMARKS INTERIOR WALL SURFACES REMARKS
EXTERIOR PRO INC. ROOF INSPECTION ROOF PLANS AND DETAILS Sketch roof plan. Include north arrows the location on the items listed below, approximate dimensions of building, roofing materials, and other relevant items located on the roof. USE THIS AREA ONLY IF DEFICIENCIES ARE OBSERVED. A - Access Hatch B - Base Flashing C - Cap Flashing D - Roof Drain E - Expansion Joint Cover F - Fascia & Gravel Stop G - Gutter System H - Vent / Fan Hood K - Chimney R - Roof Vent U - HVAC Unit J - Flag Pole W - Ponded Water P - Parapet or Fire Wall V - Vents Pipe L - Ladder S - Skylight T - Walkway Preventive Roof Maintenance Proper roof maintenance will: Increase the life expectancy of your roof Save you the high cost of roof replacement Protect your assets from costly damage For Further Information Contact us Exterior Pro Inc. 2936 Clifty dr. Madison IN 47250 (812)274-0444 www.exteriorproinc.com