Mackey Metal Roofing - Education and Advice

Metal Roofing: Cutting Metal Panels

2011-04-21T11:59:00.000-04:00

Metal Roofing: Cutting Metal Panels
by David Mackey

Wednesday, April 20, 2011

The key to trimming metal panels properly is choosing the right tools. Below, find some helpful guidelines:

● Avoid the use of a grinder (or other instruments that will spark).

○ Not only will the edge be rough & more susceptible to rust, but the sparks can embed themselves in the paint & damage the finish, leading to premature corrosion and the voiding of the manufacturer warranty.

● A pair of red and green off-set metal snips is indispensable. However, while their serration helps you make tight cuts and get purchase in difficult areas, the serrated edge you leave behind is more susceptible to rust.

● Best course is moderation.

○ Use red & green snips sparingly;

○ Opt for:

■ A pair of non-serrated metal snips (duckbill snips);

■ Or an electric nibbler where possible;

■ Put a hem where possible;

● Extra barrier from the elements

● Looks sharper / maintains color on edge

Different Panel Types

What to use where:

	Cutting the width	Cutting the length
Concealed fastener	● Red & green snips ● Non-serrated metal snips (duckbills)	● Electric nibbler ● Pair of non-serrated metal snips (and a very strong hand!) ● Brake - to put hem on newly exposed edge
Exposed fastener	● Pair of non-serrated metal snips (duckbills) ● Electric nibbler (if edge will be hidden)	● Pair of non-serrated metal snips (duckbills) ● Electric nibbler (if edge will be hidden)

David Mackey is a professional metal roofer by trade with 10,000+ hours of installation experience and President of Mackey Metal Roofing Inc. which operates North America's first 100% e-commerce platform for metal roofing panel accessible to the public. Contractors, building owners, home owners and architects visiting http://www.mackeymetalroofing.com can purchase panel, trim and accessories, as well as industry related products and tools such as paint, snow guards and power tools. Additionally, visitors can access MMR's library of industry related resources to assist them in making their roofing project a success. MMR was founded in 1999.

Metal Roofing - Choosing the Right Underlayment

2011-03-09T14:21:00.000-05:00

There are three basic types of roofing underlayment:

Felt underlayment
Rubberized asphalt underlayment.
Synthetic underlayment

Felt Underlayment (also called “tar paper”): This is the lowest cost underlayment – and for a good reason:

Absorbs moisture and wrinkles when exposed to rain or snow;
Tears when exposed to high winds;
Prone to tearing around fasteners;
Is much heavier than many of its synthetic competitors.

Rubberized asphalt: A self-adhesive and self-sealing membrane.

This is an excellent choice for low slope and water infiltration prone areas;
Self-adhesive backer which makes for a watertight membrane if installed correctly;
Self-sealing around nail heads and fasteners which is especially important for low-slope roofs;
Can be left exposed to rain or snow for a period of time without fear of leakage;
Specific brands are high-temperature resistant and well-suited to metal roofing.

Warning: Do NOT use granular coated membranes! As the metal panel expands and contracts with changes in temperature, the granules wear away both the primer and zinc / Galvalume coatings, which can lead to premature corrosion and nullify the panel manufacturer’s warranty.

Synthetic Underlayment:

A light-weight, very high-strength alternative to felt underlayment which results in decreased worker fatigue and increased safety;
Breathable varieties ensure that moisture will not be trapped against the roof deck;
Can be left for several months exposed to hot, wet and / or cold weather conditionns;
Available with a non-skid surface which results in increased rooftop safety.

Recommended Products: Tri-Flex 30 by Grace, Titanium UDL-25 by Interwrap, BREA by RoofAquaGuard

Summary:

The use of an underlayment between the roof deck and the metal panel is always recommended as a barrier against condensation. This protects both the wood of the roof deck from potential rot as well as the metal panel from being in constant contact with a moist / wet surface.
Follow manufacturer guidelines when installing the selected membrane. Overlaps, fastening patterns, weather conditions and roof deck preparation are all important factors in achieving long lasting results.
We do not recommend the use of staples when applying underlayment. Use either plastic capped nails or traditional roofing nails. Both must be coated / plated (zinc, stainless) for corrosion resistance.
We do NOT recommend the use of “tar paper” for metal roofing projects.
If you have a roof that is susceptible to ice damming or a low slope roof, a self-adhesive membrane (such as Ice & Water Shield) is recommended.
For high-slope applications, think about combining products – consider putting a self-adhesive around the perimeter, in valleys and potential water infiltration areas, and covering the balance with a light-weight synthetic.
Never use a granular coated membrane beneath a metal roof.

Metal Roofing: Health and Safety

2010-10-14T22:28:00.004-04:00

HEALTH AND SAFETY ON A METAL ROOF

Disclaimer: The information contained in this section is provided on an informational basis only. It is the responsibility of each individual contractor / homeowner / employee to comply with local, State / Provincial and Federal safety rules as set by either OSHA, CSST and / or the appropriate governing body for workplace safety. The information contained in this blog, whether it be textual or graphic, does not imply any responsibility on the part of the author for the actions of the reader.

There is no question that keeping one’s self and employees safe entails a great deal of commitment, additional costs and the feeling that production is being negatively affected. I won’t argue with that.

However, high slope roofing, especially metal roofing, is extremely unforgiving when it comes to the laws of physics. I am not talking about whether or not an employee should wear gloves or knee pads. I am talking about fall protection.

A fall from a height of 10 feet can be fatal. A fall from 20 feet + often is. Keeping people safe is smart:

Owners, employees and their families can sleep at night.
Insurance rates are kept as low as possible.
Clients recognize it as a sign of professionalism.
Employee retention increases.
Losses due to employee injury are kept to a minimum.

Here are a few simple tools to keep you and your employees safe:

1. Safety Lines / Ropes:

Types: I have always used 10.5mm diameter mountain climbing rope because it is:

Supple in both warm and cold weather;
Easy to tie knots in;
Quickly fed and stored in a duffel bag or 5 gallon bucket;
Fits easy-to-find self-arrest devices;
Easily checked for damage;
Easily cut to desired lengths;
Low cost;
Typically lasts a full season and longer.

10.5mm Climbing Rope

Knots: Almost exclusively the Figure Eight Knot because it is:

Easy to learn and execute;
Easy to untie;
Can be used in almost any situation.

Knot Diagram

Setup: Safety lines should:

Have two (2) anchor points in case one should blow out; OR
Be tied directly to a structural component of the building;
Be tied to anchors that are fastened into a structural component of the building;
Be kept away from the cut edge of a metal panel or flashing;
Be checked regularly for cuts. Damaged sections should cut out and either discarded or marked as damaged and used in non-safety applications i.e. tying scaffolding planks, lowering buckets, etc.

Rope Setup Using 2 Rappel Anchors - Each Anchored Into A Truss

Use: When used properly, ropes are both a safety measure as well as a tool.

They allow you to position yourself with extreme accuracy;
Work for extended periods of time in areas that cannot be serviced by scaffolding, ladders or lifts;
Allow you concentrate on your work without the worry of being injured by a fall.
Important Tips :
- Rope Length: Do not allow yourself to be found lying on the ground wearing a harness and attached to a safety rope. You would be surprised how many people do not take into account the following:
- Rope As A Tool: The photos are self-explanatory.


Dave Mackey Installing Valley Pan

Dave Mackey Installing Wrap On Dormer Wall

Maintenance and Storage: For a tangle-free storage solution, keep your safety rope (s) in either a duffel bag or a bucket. This is the same method of storage that firefighters use. Starting with one end of the rope, feed it into the bag / bucket while making certain not to feed it through already coiled rope. Leave the last 1 foot outside of the bag / bucket and tie it to a strap or handle.

2. Safety Harnesses:

Types:

Full-Body: OSHA-approved safety harnesses are full-body harnesses. My preference is for a harness that has multiple attachment points, with the most important one being at chest level as this allows you to work unimpeded.

Sam Hawken Wearing A Full Body Harness On A Winter Installation

Sport Harness: Not OSHA approved, but used by mountain climbers all over the world. The benefit of having one of these in your truck is that it is extremely light and you hardly know that you are wearing it. Keep in mind that you can slip out of this harness should you turn upside down during a fall.

Sport Harness

3. 3. Self-Arrest Devices:Types:

Self-Arrest Device:

Setup & Use:

The self-arrest device is attached to the rope and then attached to the worker via a carabiner. Without weight pulling them, they move freely along the rope in both directions. As soon as there is downward weight on the device, it locks on the rope.

Self-Arrest Device

4. Anchor Devices:

Types: There are many types of roof anchor devices. In addition to securing a safety line to a structural component of the building, you can use the following roof anchors

Rappel Anchor


Roof Anchor

Setup: Use a min 5/8” hex head bolt. Make certain that you are fastening into a structural component of the roof i.e. roof truss. Once fastened, if you are able to move the roof anchor something is wrong. Remove, re-position and re-fasten.

5. Ladder Attachments: Use of Standoff:

The use of a ladder standoff has several benefits:

Increased ladder stability;
No longer necessary to place ladder against the bottom edge of newly installed roof panels;
Increased safety when getting on and off the roof;
Allows for the temporary storage of materials and tools at the top of the ladder i.e. allows one person to bring multiple items up the ladder without the need to have someone take them right away.

Note: I highly recommend purchasing a standoff (s) from LadderMax LLC. We purchased two of their standoffs about 5 years ago and they continue to perform perfectly even after taking a serious beating day in and day out. Click HERE to be taken to their website (we have no affiliation with LadderMax nor do we get a commission or any form of remuneration for referred sales - it is simply an awesome product).

Ladder-Max

Metal Roofing - Re-Roofing Questions and Answers

2010-10-05T23:26:00.002-04:00

Building contractors are always looking for installation methods that will provide them with savings on labor and materials expenses. Here are some important answers to frequently asked questions.

1. Should I install a metal roof directly overtop of an asphalt shingle roof? No. Why?

Premature Failure: Metal has a high degree of thermal expansion and contraction. As the roof heats up and cools down, it moves along both its length and its width. Placed directly against the granules on asphalt shingle, this movement will scratch the underneath of the panel and eventually expose the bare steel, thus potentially causing premature failure i.e. corrosion.

Voided Warranty: The installation of a metal panel directly over top of an abrasive material, in most cases, voids the manufacturer’s corrosion warranty (this would apply to Galvalume panel only as galvanized steel does not carry a corrosion warranty).

Shape: The panel will take the shape of the underlying uneven surface and, in many cases, make shape issues visible that were previously hidden.

2. What if I lay down an underlayment before putting the metal roof on?

This is certainly a better option, but you will still have the same concerns with regard to Shape (see above) and, should the underlayment wear away or tear and expose the metal to the asphalt shingle, there exists the potential for Premature Failure which would result in a Voided Warranty.

If it is decided that this is going to be the installation method, recommended underlayments would be Grace Tri-Flex and IKO RoofGard. They are impervious to moisture and highly tear resistant. MMR does NOT recommend the use of 15# or 30# roofing felt (tar paper) for this application.

3. Does that mean I should be stripping all asphalt shingle roofs before laying metal down? No. MMR recommends the stripping of the existing asphalt shingles, however we understand that time and budget constraints do not always cooperate. Here is the recommended best practice for re-roofing over an asphalt shingle roof:

Roof Deck: Inspect the existing shingle roof to determine if it is suitable as a barrier against condensation. Remember that a metal roof will, to a certain degree, develop condensation on the underside of the panels. Those areas that show signs of previous water infiltration (underlying sheathing is soft or spongy) or damage (missing or deteriorated shingles) should be repaired accordingly and rendered watertight with the use of ice & water shield and an appropriate sealant (if necessary).

Ridges & Hips: Remove the cap shingles to avoid having a hump. If leaving exposed with the threat of rain / snow, cover with tarp or roof underlayment.

Roof Edges: Cut the overhanging asphalt shingles flush with the fascia / rake boards. This will also remove the existing drip edge. This allows you to install your eave / rake trim true to the house with a clean, tight fit to the fascia boards.

Firring (strapping):

Hips, Ridge & All Protrusions: 9 - 12 inches of width on all sides of using plywood, OSB or similar decking (thickness to match other lumber).

Valleys: 16 – 24 inches of width on either side using plywood, OSB or similar decking (thickness to match other lumber).

Gable & Eave Edges: 1” X 3” spruce firring or similar dimension light gauge steel framing, set back from edge by ¼” – ½” so that it doesn’t kick the trim out.

Interior of Roof Deck: 1” X 3” spruce firring or similar dimension light gauge steel framing, installed horizontally approximately 16” OC (use every 2^nd course of shingles are your guide).

4. All of this sounds like a lot of work. Why don’t I just strip the roof? That is a valid comment and many contractors / homeowners decide to do just that. Here are considerations for both options:

Leave Existing Roof In Place

Strip Existing Roof

Pro: No need to pay for dump fees.

Pro: No need to pay for new roof underlayment so long as existing roof is suitable as a barrier against condensation.

Pro: If using firring, creates an air barrier between the metal panel and the roof. This allows condensation that develops on the underside of the panel to dry more quickly.

Pro: If using firring, reduces thermal transfer to the underlying roof deck as the metal panel is sitting up off the asphalt shingles.

Pro: If using firring, allows for a cost effective leveling of the roof surface if required.

Pro: Reduces the burden placed on landfills each year.

Con: Does not allow a thorough inspection of the roof deck prior to installing new roof.

Con: Renders the installation of snow guards more difficult and potentially less secure.

Neutral: Not accepted by all building codes (hurricane prone areas require installation to solid deck using specific UL-90 rated clips).

Pro: Allows you to inspect the condition of the roof deck and make repairs as needed.

Pro: Provides for a smooth, flat roof surface on which to install.

Pro: Allows for the proper and thorough installation of an ice & water shield.

Pro: Allows a solid and uniform surface into which snow guards can be fastened if required.

Pro: Provides a solid surface for all fasteners.

Con: Added costs through dump & disposal fees.

Con: Added costs through new roof underlayment.

5. Do you have any pictures that clearly show the strapping of a roof? Absolutely.


Existing asphalt shingle roof left in-place - metal roof installed overtop of firring frame


Note 3/4" plywood installed around skylights to ensure solid deck for flashings.


Originally 2 distinct roof pitches, this roof was curved using firrings.

Metal Roofing - Oil Canning Explained

2010-10-05T00:03:00.000-04:00

The waves that are sometimes visible in architectural metal roofs are the result of what the industry refers to as "oil canning". As metal is formed and worked, both during the panel forming process as well as by the installers on-site, stress is introduced and can sometimes appear as waves along the surface of the panel.

Steel, copper, aluminum and other metals have been in use as roofing materials for hundreds of years and oil canning has been present throughout. Modern manufacturing techniques have made significant advances towards reducing and often eliminating surface wave, however it remains a part of most metal roofing projects to one degree or another. Panels installed in areas where there is a higher degree of stress, such as curved roof sections or over uneven roof surfaces, are more susceptible to the visible effects of oil canning.

In almost all cases, the product literature from the major manufacturers and installers of metal roofing in North America openly discusses this issue and the fact that it is part of having a standing seam roof installed. Certainly, different panel models and different roof configurations will produce varying degrees of oil canning, however even perfectly straight and flat roof sections can show signs of it.
Metal contracts and expands along both its width and its length with changes in temperature. These changes in thermal expansion and contraction will have an effect on oil canning in that certain conditions will minimize it while others will make it more evident. The reality is that it is a part of the character of a metal roof.

If you look at a wide range of standing seam roofs you will see that they frequently have a certain amount of oil canning. It is not a cause for rejection and does not reduce the effectiveness or weather-tightness of the roof. When selecting a standing seam model for your new roofing project, I recommend choosing a model that has stiffening ribs or striations along the length of the panel as this will greatly reduce or eliminate oil canning as seen by the naked eye.

Choosing The Right Paint For Your Metal Roof

2010-10-01T10:14:00.000-04:00

The repainting of a metal roof can be costly and frustrating if the correct paint is not used. This is compounded by the fact that quality metal roof paints are often not readily available at local building materials suppliers.

The following four tips are essential when choosing a paint for the repainting of a metal roof:

Tip # 1: Know What You Are Painting: Most building materials experience varying degrees of thermal expansion and contraction. This means that changes in air or surface temperature can result in changes to the physical dimensions of a building material. Metal panel is particularly prone to this phenomena. For example, if you stand near a home with a metal roof on a cold winter day, you can hear the panel pinging as it expands with exposure to the sun. This pinging noise is caused by the panel stretching along its width and length as the surface temperature rises (with exposure to the sun). When the sun goes behind a cloud, you will hear the same pinging noise which is now attributed to the panel shrinking as its surface temperature decreases. In summary, metal roof panels increase and decrease in length / width numerous times throughout the day / evening.

Tip #2: Paint Properties: Knowing that the metal roof expands and contracts, it is important to choose a paint with an appropriate degree of elasticity. Why do traditional household paints crack & peel so quickly after being applied to a metal roof? Answer: As the panel stretches, these paints are not elastic enough, become brittle and crack. Once they have formed cracks in their surface the peeling process is always close behind. Unless a paint is specifically designed for use on a metal roof and is indicated as such on the label, do not take a chance. This applies to both primer and top-coats. Selecting the correct paint while using an ill-suited primer will result in a peeling roof.

Tip #3: Choosing The Right Product: Choose a water-based acrylic, elastomeric metal roof paint. This will provide you with a product that is A) designed specifically for use on metal panel, and B) is easy to clean-up in the event of a mishap. Important Note: I often hear / read concerns to the effect that water-based paint is not as long-lasting as solvent-based. In my experience and in the experience of other industry veterans, this is simply not the case anymore. Water-based acrylics are less brittle than solvent-based paints, more environmentally friendly and easier to clean-up.

Tip #4: Paint Longevity: When applied in accordance with the manufacturer's application instructions, a quality metal roof paint should last 8 - 12 years. No manufacturer will provide a guarantee as to lifespan as the performance of the product is dependent upon the application process, however following basic industry guidelines before, during and after the painting process will typically ensure lasting results.

Choosing The Right Sealant For Use With Prepainted Metal Roofs

2010-05-04T17:19:00.010-04:00

Choosing the right sealant for your job can be tricky. It is a process that involves knowledge of both chemistry and circumstance, so guidelines should be specific to the products with which you are working.

When working with metal roofing and siding products, remember to avoid silicone-based sealants. While the flexibility and durability offered by silicone caulk can make it seem like an excellent candidate, the dry, debris-free conditions required for proper silicone caulk adhesion rarely exist on a rooftop. Additionally, the acid in silicone sealants can damage the factory applied paint on metal roofing and siding panels.

Tip: Stick with urethane-based sealants for your metal roofing and siding projects.

Metal Roof Myths: Noisy

2010-04-25T21:31:00.004-04:00

Of all of the questions that I get asked by homeowners, this is, by far, the most common. If you are installing a metal roof over open joists in a situation where the underside of the metal roof is exposed to the interior of the building, I would have to say that a rain storm will be a noisy experience! However, the question is almost always asked in relation to a residential home. When installed in accordance with modern building practices, a metal roof is no more / less noisy than other roofing materials such as asphalt shingle, tar & gravel, slate, cedar shake or rolled membrane. Roof sheathing and underlayments, attic insulation, interior ceiling construction, modern paint technology and, in some cases, metal thickness all contribute to the relative quiet of a modern metal roof.

In 10+ years of installing metal roofs I have received one complaint with regard to noise. The homeowner was disappointed because she couldn't hear the pitter-patter of the rain on her new roof!