Steel roof structures are durable, long-lasting and require less maintenance compared with other roof systems. However, poorly maintained roof systems lead to failure of the entire structure, which can be catastrophic. Despite what some may think, a steel roof is not completely watertight. If you turned it upside down and dropped it in a lake it would sink!
During harsh weather wind blows rain water into gaps, air vents and under roof sheet overlaps. Foot traffic is also a problem as it can cause punctures and tears. Water will find a way in with these too. Ponding is another problem. When water settles it will eventually make its way to the substrate. Water will get through cracks, flakes and scratches, once contact with the metal is made, corrosion begins. Standing water droplets also lead to pitting corrosion, another very serious problem for roof systems.
Is roof maintenance more important?
The roof of any building is by far the most important element in the structure. Yes, every element plays an important role but, a poorly maintained roof will eventually lead to big problems. At best it will start to leak, at worst it will collapse with devastating consequences. Flaking paint on doors, frames and flashing can be unsightly but they are not going to fall on somebodies property or worse, their head!
Steel is expensive so it’s in your best interests to look after what you’ve got. The cost of replacing a steel roof structure will be in the tens if not hundreds of thousands. Thankfully steel roofs don’t just fall apart without warning. So to avoid crippling costs don’t ignore the signs. If in doubt call a trusted expert to take a look, you can always get a second opinion. The cost of a roof inspection is insignificant compared with the cost of replacing the roof.
What are the signs to look out for with a failing steel roof?
Steel roofs suffer merciless buffeting by the heat, ice, wind, sand and rain. This combined with sea salt or other corrosive elements only intensifies the damage caused. The absence of a high-performance coating system will leave it vulnerable to attack. Roof sheets, truss components such as gusset plates and roof fixings are all at risk of corrosion.
What you need to look for firstly is, the evidence of any moisture penetration. If you find this and its been happening for a while, chances are corrosion has already started. However, don’t worry, if caught early it’s relatively easy to treat. You should carry out a close up visual check of the steel roof structure at least once a year. If you’re unable or not confident enough to do this, hire a professional. They will be able to give you advice should any repair or maintenance is needed.
The key things to look for are:
- Standing water (ponding)
- Evidence of corrosion and rust
- Water intrusion and deterioration
- Fading and chalking paint
- Blocked or poor drainage
Standing Water / Ponding
Ponding occurs on flat areas of the roof, especially the guttering. When left for long periods water will seep into the protective layer of the metal. This will leach the solvents in the coating leaving it brittle and cracked. Differential aeration corrosion is another problem with standing water in gutters. Clear anything blocking the gutter system such as leaves, moss and other organic material. If the area is badly corroded it may need treatment with a special coating system.
Evidence of corrosion and rust
Any component displaying visual evidence of rust and corrosion deservers a close inspection. You should check the depth and extend of the corroded area. Using a metal object such as a screw driver or tack hammer can be useful. Tap the area around the corrosion and listen to changes in the sound emitted. Use a scraper to remove any flaked coating to reveal what’s happening below.
Water intrusion and deterioration
This happens due to leaks or condensation in poorly maintained or ventilated roof areas. Leaks occur when corroded elements of the roof allow water to flow in. This could be via rusted sheet overlaps, roof fixings or even broken truss components causing misalignment and gaps. Condensation on the underside of a steel roof happens when the air inside the building is warmer than outside. Usually at night or during the winter months. The moisture created forms droplets of water attached to the roof components causing pitting corrosion.
Fading and chalking paint
Fading and chalking happens to all coatings eventually, some fair better than others though. Manufacturers test their coating systems well before they come to market. Resistance to fading, chalking, cracking and many other issues is measured in various environments. UV exposure, rain, polution and chemicals all contribute to stress on protective coatings. They react with the pigment in the paint causing it to fade to either a lighter or darker shade. The fading isn’t always uniform either. Chalking is a white residue that forms on coated metal roof sheets or cladding. These issues cause the resin to break down and the coating loses adhesion, eventually exposing the metal substrate.
Blocked or poor drainage
This is usually pretty easy to spot. Accumulated debris such as moss, leaves and other airborne items result in restricted drainage of rainwater. On a dry day you will see evidence of this in the form of a dirty water line. Check on a day after rainfall and if you see pools of water, you know its time to investigate. The cause of the blocked gutter may not always be visible, blocked downspouts may be where the problem lies. Either way, make sure you keep your drains cleaned so they continue doing their job for longer. They will however eventually need to be treated, by conventional means or a system such as Plygene Gutterline, so keep them clean and they will last longer.
How to protect steel roof structures from corrosion and damage?
Performing regular roof inspections at least once a year is is essential. Small issues can be caught before they turn into big problems. This is something we can carry out for you, if you would like to discuss this with us visit our contact page. Prevention is by far the best method. If you can stop corrosion, water blockage or deteriorating paint early its much less costly. However, its not the end of the world if you discover a serious issue. While every roof system is unique, there is a way to remedy almost any problem.
If you decide to carry out your own roof inspection you need to look out for the problems mentioned earlier. Standing water and rust are by far the easiest problems to identify. If you see evidence of these you need to take action very soon. Don’t be tempted to leave it for a few months and hope it doesn’t get any worse. Ponding combined with corrosion of any kind can trigger a devastating chain of events. Corrosion will spread rapidly to other parts of the roof system if left unchecked. Corroded roof fixings, roof sheet cut edges and gutter systems will all leak and allow water to penetrate other components.
Clean blocked drainage systems
You will need at least two people to carry out the work, more depending on the size of roof area. Clear and clean blocked drainage systems. Use a high pressure hose and brush to wash away organic material. You may need to spade large amounts into bags before jet washing. Spray water into the downspouts to check flow and clear any light debris. To force clear any stubborn blockages if the flow of water is badly obstructed purchase a gutter downspout brush. Once the area is dry and clean purchase Girosil roof coatings or similar to treat the areas affected. Its very important to following the manufacturers guidelines to ensure the coating system performs at its best. If you are not confident we highly recommend contacting a reputable coatings expert who specialises in industrial coatings and corrosion treatment such as ourselves.
Check and treat roof fixings
Check all roof fixings and by all we mean all. It only takes on bolt to fail and become to the catalyst for a wider corrosion problem. Thoroughly clean any affected fixings with a wire brush, cloth and solvent before treatment. Failure to carry out proper roof-fixing treatment is simply covering up the problem and allowing it to develop into something worse. There are a number of coatings available such as Seamsil 400 for treating corroded fixings. Proper treatment of corroded fixings will help to prolong the lifespan of your roof.
Touch-up corroded or faded roof sheets
Now this can be a bigger job than you think, especially where chalking or faded paint is concerned. Corroded roof sheet ends, or cut edges, should also be identified and dealt with. Clean and wash the area to be treated with a high pressure hose. Clear loose debris and flaking paint with a wire brush or better still a hand-grinder. You want to expose the metal substrate to ensure all rust has been removed. Lightly brush away any dust and clean with a solvent free cleaning solution. Apply mastic to seal the mid-sheet overlaps. Once dry apply a basecoat and topcoat by brush and roller. We recommend Seamsil 100 for this but again there are alternatives on the market. As always follow the manufacturers instructions for the best results.
How often should I paint my steel roof?
We recommend a full roof over-coating at least every 10 years, 15 years at most. This will protect your roof and reduce ongoing maintenance costs. The frequency of a full roof over-coating depends largely on a few key factors. These are environmental, existing paint quality and usage. Roof systems subject to harsh weather conditions and exposure to chemicals will require more frequent attention. The quality of the original or previous coating is also a factor. Stress through usage such as agricultural buildings, gymnasiums or dance halls also contribute to wear and paint cracking. Touch-ups should be undertaken periodically to prolong the lifespan of the roof. If in any doubt contact us or any other reputable industrial painting contractor.
If you would like to find out more about the things mentioned above take a look at some of the resources below:
- Metal roof – https://en.wikipedia.org/wiki/Metal_roof
- Corrosion – https://en.wikipedia.org/wiki/Corrosion
- Corrugated galvanised iron – https://en.wikipedia.org/wiki/Corrugated_galvanised_iron
- Sheet metal – https://en.wikipedia.org/wiki/Sheet_metal
- How Important are Regular Commercial Roof Inspections? – https://www.ddcoatings.co.uk/2247/how-important-are-regular-commercial-roof-inspections
- New Fall Protection System for Safer Rooftops – https://www.ddcoatings.co.uk/2232/new-fall-protection-system-for-safer-rooftops
- Why Steel Roofing is the Better Option – https://www.ddcoatings.co.uk/1561/why-steel-roofing-is-the-better-option