Posts Tagged ‘BUR roofing system’

Commercial and Industrial Flat Roof Systems

January 4, 2011

Commercial Flat Roof Systems

It is important that customers are educated on their roofing needs as the investment in commercial flat roofing systems are significant. Here is some information from the National Roofing Contractors Association on the most common flat roofing systems for industrial & commercial buildings to help you make your decision.

Built Up Roofing System

Built Up Roofing – BUR

These roof systems are sometimes referred to as “tar and gravel roofs” (although we don’t use actually use tar as it’s a carcinogenic) and asphalt BUR is the most common type of flat roof at this time.

BUR systems generally are composed of alternating layers of bitumen and reinforcing fabrics that create a finished membrane.  The number of plies in a cross section is the number of plies on a roof: The term “four plies” denotes a four ply roof membrane construction.  Sometimes, a base sheet, used as the bottom most ply, is mechanically fastened.  Built up roofs generally are considered to be fully adhered if applied directly to roof decks or insulation.  The reinforcing fabrics also are called roofing felts or ply sheets.

The bitumen typically used in BUR roof systems is asphalt, coal tar or cold-applied adhesive.  The asphalt or coal tar is heated in a kettle or tanker and then applied by mop or mechanical spreader.  Asphalt is a petroleum product refined from crude oil; coal tar is derived from the distillation of coal.  Cold-applied adhesives typically are solvent-based asphalts that don’t have to be heated in a kettle or tanker.

The materials used for built up roof systems include aggregate (such as gravel, slag or mineral granules), glass-fibre or mineral surfaced cap sheets, hot asphalt mopped over the entire surface, aluminum coatings or elastomeric coatings.  Asphalt BUR is the most common type of flat roof at this time. It is made up of multiple layers of reinforcing plies and asphalt forming a redundancy of water proofing layers.  The reflectivity of built up roofs depend on the surfacing material used.  Gravel is the most common and they are referred to as asphalt and gravel roofs. Asphalt degradation, however, is a growing concern. UV-rays oxidize the surface of the asphalt and produces a chalk-like residue.  As plasticizers leach out of the asphalt, asphalt built up roofs become brittle.  Cracking and alligatoring follows, allowing water to penetrate the system causing blisters, cracks and leaks.  Regular maintenance is required to ensure that a BUR roofing system achieves its life expectancy.

SBS (APP) Roofing System

Single-Ply Membranes

Single-ply membranes are factory-manufactured sheet membranes. They generally are categorized as either thermoset (EDPM) or thermoplastic (TPO or PVC). Thermoplastic materials can be repeatedly softened when heated and hardened when cooled. Thermoset materials solidify, or “set,” irreversibly after heating. Single ply membranes commonly are referred to by their chemical acronyms, such as ethylene propylene diene monomer (EPDM).

Single-ply sheet membranes are produced using one of three manufacturing processes: calendering, extruding or spread coating. The membranes may contain reinforcement layers. Common reinforcements for single ply membranes include polyester fabrics or scrims, glass fibre, or a felt or fleece backing.

A finished sheet’s thickness typically is referred to as mil thickness. Common mil thickness for these sheet membranes range from 30 mils to 60 mils. Single-ply membranes can be installed fully adhered, mechanically attached or held down with ballast. Most single-ply roof systems do not receive surfacing. In many instances, a combination of attachment methods are used to secure a roof system.

For instance, an insulation may be mechanically attached to the substrate with the roof membrane fully adhered to the insulation.

EPDM Roofing System

EPDM A Single-Ply Membrane

Ethylene Propylene Diene Monomer (EDPM) roofing is an efficient rubber roof style used on low-slope roofing surfaces. It is a synthetic rubber most commonly used in single-ply roofing because it is readily available and relatively simple to apply. It is also called Single Ply Membrane and it is one of the common types of low-slope roofing. It’s been in use on roofs in the Canada since the 1960’s. When properly applied, it has a life cycle of 15 to 25 years. It is great for preventing leaks and is often installed for roofs that have problems with weathering, failing joints, and inflexibility. It is relatively inexpensive as well as simple to install as compared to BUR. Compared to conventional built-up roofs, it is also much cleaner and doesn’t emit the odors and fumes that are often associated with built up roofing systems. (Although Conestoga Roofing uses an “odourless kettle” when it comes to applying BUR.) Vulcanized EPDM is the most common type of EPDM roofing system. Non-vulcanized EPDM is typically used for flashing purposes.

There are three methods of applying EPDM:

  1. Fully adhered EPDM uses water-based or solvent-based adhesives to adhere the EPDM rubber to the substrate.
  2. Mechanically fastened EPDM is attached to the substrate by manufacturer-approved mechanical methodology.
  3. Loose-laid membranes are secured only at the perimeters and any penetrations. A ballast of round river rock or concrete pavers is used to hold the materials in place. The river rock is usually installed at a rate of 1000 – 1200 pounds per square (100 square feet of roofing surface) and the pavers typically weigh 20-pounds per square foot. Structural integrity is of paramount importance with a loose-laid roof system. The seams are sealed using either an adhesive or a splicing tape.

EPDM Benefits:

Highly dependable, economically beneficial, high durability, and high efficiency makes EPDM an attractive option to any building owner looking to a commercial, industrial and institutional roofing contractor for a new roof or an upgrade to the existing roofing system. Additionally, an EPDM roof will often come with long warranty, low maintenance requirements, low installation labor costs, and generally garner rather easy code approvals. For regions subject to potentially catastrophic weather experiences, such as hurricanes – EPDM roofs have very high resistance, making them quite practical for those who live in those areas.

Advantages of EPDM

EPDM roofs are highly resistant to weathering, ozone, and surface damage. It is flexible in cold weather and still has high fire and heat resistance. You can’t go wrong choosing EPDM for low-slope roofs and flat roofs that need to be waterproof and durable against the harsh Minnesota weather.

TPO Roof System

TPO & PVC

Another example of a Single-Ply Membrane is the thermoplastic TPO or PVC roofing system. These membranes can be repeatedly softened by heating or hardened when cooled. Because of the materials’ chemical nature, thermoplastic membranes typically are seamed by heat welding with hot air or solvent welding.
The most common thermoplastic roof membranes are PVC and TPO. The following provides general descriptions of these two systems .

Thermoplastic Olefin (TPO)
TPO membranes are produced by calendering with lamination, extrusion with lamination, or extrusion-coating techniques. TPO sheets are a blend of polypropylene and ethylene propylene polymers and usually are reinforced with polyester. TPO sheets contain colorant, flame retardants, UV absorbers and other proprietary substances to achieve desired physical properties.

  • Sheet widths range from 6 feet to 12 feet wide
  • Sheets are typically 40 mils to 100 mils thick
  • Seams are sealed by heat welded with hot air
  • TPO membranes Commonly are white or black
TPO roofing

PVC sheets are produced by calendering, spread coating or extruding, and typically are reinforced with polyester or glass-fibre mats or scrim. PVC sheets contain plasticizers and stabilizers, as well as other additives to impart flexibility and achieve other desired physical properties. Some membranes are available with nonwoven fleece backing adhered to the underside of a sheet.

  • Sheet widths range from 6 feet to 12 feet wide.
  • Sheets are typically 45 mils to 90 mils thick.
  • Seams are sealed by heat or chemical welding.
  • PVC membranes are produced in numerous colors, though gray and white are the most common.

Modified Bitumen

Polymer-modified roof membranes are composed of reinforcing fabrics that serve as carriers for the hot polymer-modified bitumen as it is manufactured into a roll material. MB roof system membranes are composed of multiple layers, much like BUR membranes. MB roof systems typically are installed as a two-ply system and almost always are fully adhered.

There are two types of MB roofing membranes:

  • SBS polymer-modified bitumen membranes commonly are installed in hot moppings of asphalt (similar to BUR systems) or cold adhesive. Some SBS modified membranes are self adhering; that is, they contain an adhesive backing.
  • APP polymer-modified bitumen membranes typically are heat-welded or torch-applied.

Generally, APP modifiers impart a “plasticized” quality to asphalt, and SBS modifiers impart a “rubberized” quality to asphalt. MB membranes and EPDM a thermoset membrane, often are confused by consumers because of colloquialisms used by roofing contractors. MB and EPDM membranes are sometimes called “rubber roofs.”

Modified Bitumen

Surfacings for MB membranes include aggregate surfacing, mineral surfacing, metal foil-laminate surfacing and smooth liquid-applied surfacing.

Look for a roofing contractor that specializes in different types of roofing, and can help you to decide which will work best for your building – residential or commercial.

If you are planning to install a flat roof for your building, the best thing that you can do is to contact a professional roofing service that has extensive experience working with commercial roofing systems.

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The Benefits Of Built-up Roofing Systems

October 19, 2010

Built Up Roofing (BUR)

Built Up Roofing (BUR) Systems From A Minnesota Roofing Contractor

  • Superior Water Resistance
    A multi-layered system of reinforcement offers more protection, reducing the risk for leaks, when a single-ply system only offers one chance at preventing a leak.  Also, nothing compares to asphalt when it comes to making a roof water resistant.  Asphalt is the glue that holds a Built-Up Roof together.  It seals and protects the entire roof, delivering up to five times greater water-resistant thickness.
  • Easier Installation
    When working with hot Built-Up Roofs, the multiple plies get fused together using hot-mopped asphalt to create a monolithic barrier.  Every inch is firmly and completely adhered over the entire roof area, without the need for ballast or fasteners.  Single-ply systems require ballast or fasteners because they are generally laid loose.  But ballast (such as stones) increases structural load and can be blown off by strong winds.  Fasteners can also create less stress points and additional opportunities for moisture leakage.
  • System Longevity
    Each ply of a Built-Up Roofing System contains a mat of glass fiber reinforcement while most single-ply systems contain no reinforcement at all.  When multiple plies are combined and positioned between layers of water-resistant asphalt, the result is a longer lasting roof.
  • Easy and economical to maintain.  And if necessary, can be repaired with conventional, time-proven materials, resulting in extended service life.
  • Product and material improvements have enhanced an already high-quality system.

Time tested and proven to be one of the best commercial solutions today, Built-Up Roofing Systems or “BUR” Systems have been around since the mid-1800s.  They should definitely be a strong consideration for your next roof.

Flat Roof Systems

October 12, 2010

Types Of Flat Roof Systems

Flat roof systems are roofs that are built so that they are nearly flat.  They are not completely flat; otherwise water would build up on the roof (called ponding) and would eventually start to get inside the building.  Flat roofs are built with a slight incline.  They are required to have at least a one-eighth-inch difference in height over each foot of the roof.   There are five main types of flat roof systems.

Roll Asphalt
A roll asphalt roof is made of material that is rolled onto the roof over roof felt and nailed down or applied with cold asphalt cement.  It is usually covered with a granular mineral surface, which looks like gravel.  The base material can be organic felt or fiberglass felt that is saturated in asphalt.  This is the cheapest building material, but it usually doesn’t last much beyond 10 years.

Single-ply
Single-ply flat roofs are composed of a single layer of a plastic or rubber-like compound.  Some of the more popular materials used today are thermoplastic polyolefin (TPO) and polyvinyl chloride (PVC), which are both very good at reflecting heat, which saves on cooling costs in the building.  Ethylene propylene diene monomer (EPDM) is also popular because it also cools well when white EPDM is used, and it is easy to install.  Rubberized asphalt is also used.  Single-ply roof systems, depending on the materials, can be self-adhered, applied with hot asphalt or installed by heating the back of the material with a torch.  Warranties for single-ply roofs usually are for 10 to 12 years.

Multiple-ply
Multiple-ply roof systems are also known as built-up roofs (BUR). These are made by overlapping rolls of felt or mats that are alternated with layers of asphalt.  This is covered by a granular mineral surface, ballast or tile to protect the layers.  These roofs can last 10 to 30 years.

Modified Bitumen
A modified bitumen roof is a multiple-ply roof that is made with modified bituminous membranes, which are made out of a blend of asphalt and a polymer.  This allows the asphalt to take on characteristics of the polymer, which is similar to materials used in single-ply roofs.  The modified bitumen roof is covered in a mineral or gravel surface, or a liquid coating that provides reflectivity.

Flat-seamed Metal
Flat-seamed metal roofs are made out of small sheets of metal that are soldered together.  The sheets are usually designed to look like tile or shingles.  The most common metals used for roofs today are copper, lead-coated copper or stainless steel. Metal roofs are light and reflect heat well, but are more expensive.

Commercial Roofing and Remodeling Contractor

September 10, 2009

Built Up Roofing Systems

Built Up Roofing Systems have stood the test of time

Built Up Roofing Systems have stood the test of time.  Not only are they still used extensively for new construction projects, they are one of the most common types of commercial roofing systems in the world.  Built up roofing systems are designed to endure harsh weather conditions, in harsh climates, all year round, and we all know what kind of extremes exist in the Midwest.

Price Benefits of Built- up Roofing:
Inexpensive over the entire life cycle
Great “bang for your buck”
• Versatile options to choose from…you can choose the right system for your budget

Maintenance Benefits of Built-up Roofing
• Easy to repair
• Low maintenance

Performance Benefits of Built-up Roofing
• Multi-layer protection
• Thermal performance
• Fire and life-up performance
• Durable/Reliable
• Suitable for all types of roof decks
• Has a successful 100+ year track record
• Redundancy of layers reduces chances of leaking
• Superb tensile strength
• Tolerates high roof traffic well
• Strong/Tough…today’s formulas resist weathering
• Insulated systems achieve high thermal value
• Adapts to meet any penetration or flashing detail configuration

United Roofing & Remodeling is able to offer our customers exceptional warranty programs; some will last as long as 20 years.  We have been serving the Twin Cities and surrounding areas of St Louis Park, Edina, Minnetonka, Bloomington, Plymouth, Excelsior, Wayzata, Eden Prairie, Chanhassen, and Chaska, for 20+ years, maintaining, repairing and installing commercial roof systems.

Our experts at United Roofing & Remodeling will work closely with you to ensure that the proper system is installed and will meet all of your specifications.

Are you looking for commercial roofing contractor?  Simply contact us at our office at 612-617-1717
or Request a Quote online