Do you want to learn how to overlap corrugated metal roofing?
It is just one of the many steps in installing this type of metal roofing sheet, and there are many different kinds available in the market today.
And if you are a homeowner interested in revamping your roofing system, corrugated metal might be a viable option for your household.
Corrugated metal roofing sheets are a type of roofing that is made by a roll-forming machine, particularly shaped and designed into alternating grooves and ridges to achieve maximum strength.
The shape of corrugated roofing is the chief reason for its durability.
It needs support strips to make it stable since the screws go through the rib peaks. And the curve of the valleys and ribs keeps the screws from properly sealing.
Due to its corrugated shape, fragile and light materials like aluminum can be made to be resilient from years of harsh weather conditions.
The most common and popular one is galvanized steel, with is often used as a base roofing material. Also, corrugated roofing is available in the tin form.
These roofing sheets are mostly utilized for sheds, garages, and porches.
Table of Contents
How To Overlap Corrugated Metal Roofing
Installing and overlapping corrugated metal sheets on your roof can be especially tricky, and in doing it properly, you will need these tools and materials:
- Work gloves
- Safety goggles
- Measuring tape
- Hammer
- Corrugated metal sheets, it can either be galvanized steel or tin
- Paint (optional)
- Paintbrush (optional)
- Polyurethane sealant
- Ridge peak
- Screws
- Washers
- screwdriver
- Utility knife
- Roofing cement
- Roofing nails
- Roofing felt
- Roofing staples
Here are the steps in installing and overlapping corrugated metal sheets on your shed, porch, or garage roof:
- Take measurements on your roof
There is an easier way to measure your roof without climbing on top of it.
You only have to measure its width and length and multiply them together. If your roof has a peak, you will have to measure both sides.
You will have to include more than the measured number since each corrugated sheet needs to overlap with each other. Professional roofers advise about four inches of overlapping space.
Possible issue
Climbing a roof poses many difficulties, and if you are not careful, it can be potentially disastrous. If you are going to do specific tasks on your roof, like taking measurements, you have to take the necessary steps to make sure of your safety.Possible workaround
Follow these helpful roof-climbing tips:- Always have people present to help you
To climb the roof with minimal difficulty and free of any possible danger, you need to have at least one person to help you. The other person holds the ladder as you climb up the roof.
Ladders are known to collapse or fall once you reach the top of the roof, and that is the worst thing that can happen. If you do not have someone to help you hold the ladder, you have to be sure it is secure in place on the ground, and its feet on the proper angle.
Another good workaround is to put something large and heavy in front of the ladder, so if it slides it cannot go far. - Do not put you ladder against the gutter
When placing the ladder against the wall of your house, make sure you are not putting it against the gutter.
Roof gutters are usually made of thin aluminum sheets, and situating the ladder there may end up denting it. If you cannot find anywhere to lean the ladder safely, look for a gutter screw to lean the ladder on, and this way, it can do minimal damage. - Do not walk on the rooftop shingles/corrugated metal sheets
Any roofing you have, be it shingles or corrugated metal roofing is not meant to be trodden on. Walking constantly over them can potentially damage them and shorten their lifespan.
If you have to walk over them to take measurements, always tread lightly, and do not drag any tools or equipment across the roof. - Do not underestimate the height
If you are looking from the ground up towards the roof, it may not look steep. But it is a different story once you are on top looking down.
If you have a fear of heights or vertigo, you probably should not climb it and instead ask for help from a professional roofer.
- Always have people present to help you
- Purchasing the corrugated metal sheets
You can utilize various-sized sheets, which will depend on the area of your roof.
You will have the option of buying massive sheets measuring thirty-two feet long and cutting them to your preferred size.
Or you can buy pre-trimmed sheets measuring ten to twelve feet in length in any home improvement center.
Cutting the sheets will require tin snips, an angle grinder, or a saw.Possible issue: oil canning
It is also known as stress wrinkling or elastic buckling. It refers to the waviness in the flat surfaces of all metal roof types and can happen to any panels like aluminum, steel, copper, or zinc.
There are many reasons why oil canning can happen:- Over production
- Habitual stress from roll-forming and coil slitting panels
- Not enough space allotted for contracting and expanding
- The original form of the structure changes due to movement and tension of the panels
- The installers do not properly use, handle, and store the roofing sheets
Possible workaround for oil canning
- Buying thicker metal roofing sheets
- Using a rib roller profile to flatten any buckled areas
- Selecting matte or low-glass finish to lower reflectivity, thus decreasing the visibility of oil canning
- Purchasing stretched or tension-level metal
- Lay the metal roofing sheet over a flat roof deck
Possible issue: leaking
Here are many reasons why your corrugated metal roofing sheets may leak:
- Strong rains
- Melting or heavy snow
- Ice damming
- Strong winds
- Structural damage
- Installation error
- Other harsh weather conditions
Possible workaround for leaking
Make sure you select a contractor with a good reputation and track record of successful roofing installations, which will lower any probabilities for leaks to happen.Possible issue: scratching and scuffing
Your corrugated metal roofing sheets will likely be subjected to scuffing and scratching at least one point in their lifespan. Its manufacturers have taken necessary precautions in ensuring that the sheets are not scratched during the slitting procedure, or when they are being transported.
Here are some situations when scratching and scuffing can happen to the metal sheets:- Whenever the corrugated metal roofing sheets are not properly coiled or recoiled that causes them to rub with each other and strip the coating
- No edge guards are utilized to protect the edges of the sheets when shipped
- Lifting devices are not properly handling the sheets
- The roll-forming machine malfunctions and the sheets are accidentally scraped by the machine
- Tools and other equipment are accidentally dropped or scraped on the sheets
- The roofing sheets are walked on by contractors and installers
Possible workaround for scratching and scuffing
If you notice any scratches or scuffs on the metal sheets, inform the manufacturer and contractor at once. These can be fixed by a touch-up pen or paint made to match the roof color.
However, if you notice a gauge going to the core of the sheet, it should be substituted immediately.Possible issue: corrosion
Corrugated metal roofing sheets are usually chosen because they can stand against degradation and corrosion for many years. Contractors and manufacturers can help you to select the most suitable roofing sheets for your home.
Corrugated roofing sheets are designed to be corrosion-resistant, but there are situations when corrosion can still happen:- Underside corrosion- If the metal sheets are not properly coated in the underside, it can still corrode
- Saltwater corrosion- If your home is close to the seacoast, your metal roofing sheets can corrode. Other materials like zinc or aluminum will work better in coastal areas
- Dissimilar materials- Different types of metals are placed together can cause negative reactions
- Cut edges- Edge creep will happen, which means the occurrence of rust at the cut edge
Possible workaround for corrosion
Corrosion will likely occur during the lifespan of your corrugated metal roofing sheets. The best workaround is to know the various types of metal roofing sheets, the different kinds of paint systems, and the environments they can work in.Possible issue: Dissimilar materials and metals
If you combine different types of metal sheets and materials in your roofing system, it can result in premature degradations, staining, and failure.
For instance, Galvalume roofing sheets should not be installed with other materials like iron, copper, lumber, or concrete, which leads to galvanic corrosion.Possible workaround for dissimilar materials and metals
Before purchasing any roofing materials, have a clear discussion with the contractor of the type of materials that will come into contact with your metal roof.
Here are some materials and tools that may come into contact with your corrugated metal roofing sheets that would not have a negative effect on them:- Gutters
- Panels
- Trim
- Rivets
- Fasteners
- Flashing materials
- Lead pipe boots
- Fascia
- Chimneys
- Drip edges
- Wall materials
- Siding
- Roof mounted air conditioners
- Swamp coolers that has copper drain pipes
- Cedar shake shingles
Possible issue: fading and chalking
Chalking pertains to the white residue on a coated or painted metal sheet. It will appear when the paint resin breaks down from UV exposure.
Fading happens when the paint pigment on the metal breaks down because of pollution, chemicals, etc., that causes to change in color.
Your metal roof may fade unevenly if you are not evenly exposed to those harmful substances.Possible workaround of chalking and fading
These issues will likely occur no matter where you live but how much will appear will depend on the substances and environment your metal roofing sheets are subjected to.
Fortunately, most metal roofing manufactures provide warranties that cover chalking and fading. - Install the roofing felt
The roofing felt’s purpose is to provide a layer of insulation. It will be useful if you are installing a metal roof for an outdoor structure like a patio.
Use the utility knife to cut the roofing felt to the size as previously measured. It will lay horizontal by the roof’s plywood deck.
Use roofing staples to fasten the roofing felt, and be sure to overlap each one by about four inches.Possible issue: Alligatoring
After installing the roofing felt, many issues can likely happen to it, and one phenomenon is called alligatoring.
As time passes, the roofing felt ages and loses its elasticity. It will result in cracking, bubbling and will resemble alligator skin.Possible workaround for alligatoring
The roofing felt has reached its limit and deteriorated, so you need to substitute it with a new one.Possible issue: moisture and leaks
The most common issues for roofing felt are moisture and leaks, which often go hand-in-hand.
These are not big problems and can be dealt with immediately and effectively.
When this happens, moisture will creep into the roofing felt and cause fungus and mold.Possible workaround for moisture and leaks
The best way to deal with watery leaks and moisture is to have your roof regularly inspected and maintained.Possible issue: buckle in membrane
Roofing felt is usually made of asphalt in one continuous roll, and as time passes, your house will shift and settle. And your roof will also shift and settle along, thus buckling in the asphalt membrane.
A constantly buckling roof is not safe for people living underneath, resulting to further issues as time passes.Possible workaround for buckling in membrane
The only way to fix buckling in the roofing felt is to replace it immediately.Possible issue: pooling of water
There will be a possibility of rains and snow accumulating in the roofing felt. As time passes and your house shifts and settles, your roof might slightly change position and would not be as level as it once was.
It will result in water pooling in some spots and will leak underneath. If this continues and remains unfixed, the roofing felt will deteriorate and shorten its lifespan.Possible workaround for pooling of water
The best way to fix the accumulation of water in the roofing felt is to replace it immediately with a new one.Possible issue: flashing
Roofing felt is similar to other roofing materials wherein it contracts and expands with temperature and weather changes.
And as time passes, the constant contraction and expansion can cause the flashing to withdraw from the corners and edges of the roof, which leads to leaks and moisture being trapped.Possible workaround for flashing
The best way to avoid this issue is to have your roof regularly inspected and maintained. However, if you see that the roofing felt has too much deterioration in the flashing, you will need to replace the roofing felt. - Install the first corrugated metal sheet
You will begin laying the first sheet at the bottom corner and proceeding across.
After finishing each row of corrugated sheets, proceed with a new row. Of which has to overlap from the old rows by about four inches.
The first sheet should be positioned in a way that it overhangs at the edge for about four inches.
You aim to start at the bottom and slowly go higher until you reach the roof peak.
Use a screwdriver to screw the washers into the wood screws and onto the plywood with the roof.
You want the screws to have the right amount of tightness but not too tight to crumple the metal sheet.
The screws should be about eight inches along the bottom and outside edge of the sheet. - Possible issue: incorrect measurements
Not correctly measuring the roofing sheets is the easiest way to incur additional costs and delay the installation process, and will lead to ordering roofing sheets of the wrong size.Possible workaround of incorrect measurements
Always make accurate measurements first before ordering the roofing sheets, and avoid ordering on a job that is not built to order, only to make the lead times faster.Selecting the wrong type of roofing sheets
Sometimes, problems will happen if you choose the wrong metal roofing sheets to install. There is a wide variety of roofing panels to select from and is a common mistake to order the wrong kind.Possible workaround for selecting the wrong type of roofing sheets
You have to make sure that the corrugated roofing sheets you have selected are of the right type and correct roof pitch.Possible issue: incorrectly installing the fasteners
When your corrugated metal roofing sheets are leaking water, the most common reason is the fasteners are not installed correctly.
The fasteners should be properly screwed in and not over tightened or under tightened.
If the washer is off the center, the fasteners are too tightly screwed in. And if the gaskets are not compacted steadfastly against the surface, the fasteners are not tight enough.Possible workaround for incorrectly installing the fasteners
You have to make sure that the fasteners are in just the right amount of tightness.Possible issue: wrong sealant
Sealants are for covering any possible leaks from natural elements that will compromise the roof. These issues will happen if it is not applied properly.Possible workaround for wrong sealant
You have to make sure you are applying to seal the proper way and particularly made for metal roofing sheets. Other types of sealants may not adhere to the type of metal roof you have.
The sealant should also be flexible enough to expand with the metal sheets without breaching its seal.Possible issue: flashing not correctly attached
The role of the flashing in roofing structure is to keep water from entering at a joint or roof penetration. If not fasted properly, moisture and water can leak through.
Any spot that penetrates the roofing surface, like chimneys, ventilation ducts, skylights, etc., should be installed with flashing surrounding them.Possible workaround for flashing not correctly attached
You have to make you are using the right kind of flashing that comes with the correct size so that the area is covered completely.
Flashing seams should be sealed properly to let the water flow through on top of the material and prevent it from entering underneath the roofing.Possible issue: not enough metal roofing experience
Each roofing material has specific installation procedures, and problems will arise if the roofer installing the corrugated metal roofing sheets lacks the proper knowledge.Possible workaround for not enough metal roofing experience
You have to make sure you are hiring a professional and qualified contractor or roofer that knows how to install corrugated metal roofing sheets. - Finish the first row
When you are about to install a second corrugated sheet, be sure to overlap by about four inches or at least one rounded corrugation. It will aid in weatherproofing the roof.
Then properly drive in screws at the bottom and overlapping edge of each corrugated sheet.
You may need to trim the last sheet of each row to fit the area of the roof. But do remember the necessity of overlapping it.
Use tie snips, angle grinder, or saw for cutting.Possible issue: incorrectly using an angle grinder
You might not have difficulty in using snips or saws for trimming the corrugated metal roofing sheets, but using an angle grinder might be a little tricky.
An angle grinder is a type of handheld power tool that has an abrasive wheel. It is usually found on construction sites for polishing, grinding, and cutting.
It is crucial to use it properly, and utilizing the wrong wheel for a particular task can be disastrous. Here are some of the ways that an angle grinder can harm you:Contact with the wheel
A typical angle grinder can cut concrete, stone, metal, and other tough materials, and it would have no problem cutting through human bones and flesh.Possible workaround
These will happen if you do not have the proper guarding, so make sure that you are wearing protective gloves and safety guards are in place. You also have to be always alert and deeply focused while using the angle grinder.Wheel breakage
Every tool with an abrasive wheel has the risk of breakage, and especially with angle grinders.Possible workaround
You can keep the risk at a minimum by always checking on the discs, safely using and mounting the angle grinder.
You can also lower the risk by understanding the limitations of the disc you are using. It means only using a disc in good condition, within the speed limitation and expiry date.
Only use the abrasive wheel on the tool it is intended for. Many accidents will happen if the wheel is mounted incorrectly or if the equipment is incompatible with the disc.Contact with projectiles
Projectiles can happen due to wheel breakage or by the type of materials being cut or ground.Possible workaround
You cannot help projectiles from occurring, but you can keep them at a minimum by using the right abrasive wheel, tool, and settings for the appropriate material.
Also, wear proper protective gear that can shield incoming projectiles to the head and eyes.Kickback
Kickbacks can happen when the angle grinder jams on the material while cutting or grinding. It will likely happen if you are utilizing the wrong kind of wheel or on the wrong speed setting.Possible workaround
You can stop this from happening by using the right kind of abrasive wheel for the material you are cutting or grinding and on the right speed setting.
Make sure you have been properly trained in mounting and changing the wheels whenever they have become too worn out.Entanglement
Whenever using an angle grinder in working on a difficult task, you have to wear proper work clothes. If it is too loose, it might get caught in the rotating disc and cause injuries,Possible workaround
Make sure you are not using long baggy clothes that can get caught in the wheel. Get rid of any rags and waste materials that can get entangled.Fire
Sparks will fly whenever you use an angle grinder. You are not able to stop this from happening, but there are precautions you can do to minimize fire from happening.Possible workaround
Always be aware of where you are while using the angle grinder and remove any flammable materials in your vicinity. - Complete the first side of the roof
Begin laying down the next row of corrugated sheets starting from the last sheet of the previous row. Do not forget to overlap it by four inches.
Do the same thing to complete the first side of the roof.Possible issue: incorrect measurements
Not measuring the roofing sheets correctly is the easiest way to incur additional costs and delay the installation process, and will lead to ordering roofing sheets of the wrong size.Possible workaround of incorrect measurements
Always make accurate measurements first before ordering the roofing sheets, and avoid ordering on a job that is not built to order, to make the lead times faster.Possible issue: not enough metal roofing experience
Each roofing material has specific installation procedures, and problems will arise if the roofer installing the corrugated metal roofing sheets lacks the proper knowledge.Possible workaround for not enough metal roofing experience
You have to make sure you hire a professional and qualified contractor or roofer that knows how to particularly install corrugated metal roofing sheets. - Install the corrugated sheets on the other side of the roof
Do the same procedure as before until you slowly reach the peak of the roof.Possible issue: incorrectly installing the fasteners
As you are close to finishing installing the corrugated roofing sheets, make sure they are not leaking water and the most common reason is the fasteners are not installed correctly.
The fasteners should be properly screwed in and not over tightened or under tightened.
If the washer is off the center, the fasteners are too tightly screwed in. And if the gaskets are not compacted steadfastly against the surface, the fasteners are not tight enough.Possible workaround for incorrectly installing the fasteners
You have to make sure that the fasteners are screwed in just the right amount of tightness. - Fasten the peaked ridge cap
Complete the topmost portion of your roof by including the peaked ridge cap, which looks like the shape of your roof.
Make sure to situate it to overlap the metal rows underneath, and Fasten washers screws and flashing to make everything secure in place.Possible issue: flashing not correctly attached
The role of the flashing in roofing structure is to keep water from entering at a joint or roof penetration. If not fasted properly, moisture and water can leak through.
Any spot that penetrates the roofing surface, like chimneys, ventilation ducts, skylights, etc., should be installed with flashing surrounding them.Possible workaround for flashing not correctly attached
You have to make you are using the right kind of flashing that comes with the correct size so that the area is covered completely.
Flashing seams should be sealed properly to let water flow through on top of the material and prevent it from entering underneath the roofing. - Seal the seams
Apply roofing cement or sealant to seal off all the exposed seams. Once done, let it dry for about twelve hours.Possible issue: wrong roofing cement or sealant
Sealants or roofing cement are for covering any possible leaks from natural elements that will compromise the roof. These issues will happen if it is not applied properly.Possible workaround for wrong roofing cement or sealant
You have to make sure you are applying to seal the proper way and particularly made for metal roofing sheets. Other sealants may not adhere to the type of metal roof you have.
The sealant should also be flexible enough to expand with the metal sheets without breaching its seal.
How To Repair A Corrugated Roof?
You may think that your corrugated roof is tough and unaffected by weather elements, and it is still impervious to leaks.
These occurrences are quite common to these types of metal sheets. But the good news is you can fix it with ease, as long as you have the proper tools and know-how.
Instead of calling a professional roofer or repairman, you are able to do the repair work and save on unnecessary costs.
Tools & Materials That You Need
- Harness
- Ladder
- Rag
- Safety goggles
- Corrugated sheet
- Watertight sealing tape
- Lacquer thinner
- Screws or roofing nails
- Screwdriver or hammer
DIY Steps In Fixing A Corrugated Roof
- Prepare yourself and the things that you will need – Take the ladder and place it firmly on the ground. If you are using an extendable ladder, be sure to secure the extensions.
Also, make sure you are wearing appropriate work clothes and safety gear like goggles and harnesses. - Look for the leaks – Looking for the leaks might be difficult and tricky. Your starting point should be the area where the leak is supposedly happening.
Look for a spot where the ceiling tiles are wet; it is a common sign of roof leaks. Start from there and closely examine going backward to the source.
The source of the leak might be a couple of meters from the area where the water drips.
The common leaky spots are chimneys, skylights, wall step flashings, and other low ceiling areas.
Unresolved roof leaks can go down as far as the cellar since water runs down the outside walls. - Patching up the leak – After finding the leak, use the rag to wipe any liquid remaining. The drier the area, the easier and quicker it can be fixed.
After wiping the area clean, apply a small quantity of thinner.
Cover the entire spot that needs to be patched with the watertight sealing tape.
Be sure that the sealing tape is designed to patch up metal so that it can stick. It is also rain and ultraviolet-resistant.
If the damaged spot is too big and patching would not work, you will have to remove the whole corrugated sheet.
Begin by pulling out the screw or nails from the damaged and corresponding sheets. You will notice that the corrugated sheets are overlapping from each other, so you will need to follow its exact placement.
Corrugated roofing has special screw or nails, so be sure you are using them since they are watertight and weather-resistant.
Hammer or screw them down the ridges rather than the lower curve to make them more watertight. About twenty screws or nails will suffice. Do the same thing to the corresponding sheets. - Regular inspections – You can prevent any further leaks from occurring again by inspecting in regularly.
It is recommended to inspect it after harsh weather has happened, like typhoons and tornados.
Also, make it a habit to clean and unclog the gutters once in a while to keep them in shape.
FAQs
How Long Will My Roof Last?
There are a few factors that will make a particular roof have a long or short lifespan. Aspects like climate and maintenance can impact the roof life.
An asphalt roof with the right weather, precautions, and care will last about twenty years.
Metal roofs like corrugated metal roofing can last about fifty years.
How Much Will A New Roof Cost?
The answer will depend since each home is different. The best way to find the solution is to consult a professional roofer to give you a quote.
Can I Insure My Roof?
If you have homeowner’s insurance, your roof is protected from any damage. It most likely has a ten-year warranty, which you can have fixed for free by a professional roofer.
How Would I Know That My Roof Is Failing?
If you like to know about the health of your roof, you have to know how old it is.
If an asphalt roof is older than twenty years, then it has to be replaced.
Inspect your roof, look for any shingles that are cracked, curled, or missing. If there is, then your roof is overdue for a replacement.
Is It Alright To Have My Roof Installed In Winter?
Catastrophes may happen, and your roof will be damaged and needs to be fixed as soon as possible.
A new roof can still be installed in wintertime, as long as it is done with great care, store the materials properly, and wait for days to clear.
Conclusion
Learning many things about roofing, like how to overlap corrugated metal roofing, is essential knowledge for a responsible homeowner.
This way, once the time comes when you need to replace or have it fixed, you have a wide breadth of practical knowledge about roofing that comes in handy.
