How to repair a metal or corrugated roof
Instapatch moulds into the profile of metal and corrugated roof sheets, so it can seal small holes, splits, rust spots and leaking fixings. It cures hard in daylight and can be painted to match the roof.
What you'll need
- Instapatch Standard patches big enough to cover the damage with room to spare. The order wizard will suggest a size.
- UV Curing Primer and a brush if there's any rust. It's optional on clean, sound metal.
- Scissors or a sharp knife
- Gloves and protective clothing
- Surface cleaner or degreaser, and clean cloths
- A wire brush or scraper for loose rust and flaking paint
Before you start
- Take care on any roof. Rooflights and badly corroded sheets may not take your weight, so never step on them. Use a proper ladder or access equipment.
- The surface must be dry and free from dust, grease, waxes and loose material.
- Avoid the hottest part of the day. A metal roof in strong sun can get very hot. Morning or evening is better in summer.
- The patch cures in air temperatures from -15°C to 70°C.
- Only open the patch when you're ready to use it. It can start to cure within minutes in daylight.
Steps
Brush off loose rust and flaking paint, then clean the area with surface cleaner and let it dry.
If there's rust, brush on UV Curing Primer and let it dry fully. On clean, sound metal, primer is optional but improves adhesion.
Shape the patch with scissors while it's still in its packet.
Peel the release film from one side and press the patch on straight away. Mould it into the corrugations and apply firm pressure all over.
For a leaking screw or bolt, place the patch over the fixing and press it down firmly around the head.
If you want to paint the repair, peel off the top film now for a matt finish. Leave it on for a gloss finish that can't be painted.
Leave the patch to cure in daylight. Keep pressing the edges into the profile until it hardens, so the corners don't lift.
Cure timing for this surface
Daylight cures the patch in 15 to 45 minutes, depending on how bright it is. Roofs in direct light cure at the quicker end.
After the repair
Once it has hardened, the patch is waterproof and highly resistant to weather and UV. You can drill it, screw through it, sand it or paint it to match the roof.
Common questions
Remove any loose rust and flaking paint first, then use UV Curing Primer before patching.
Place the patch over the fixing and press it down firmly around the head, so it covers the fixing and the sheet around it.
Yes, if you peel off the top film straight after applying the patch.
Common mistakes to avoid
- Leaving loose rust or flaking paint under the patch
- Not pressing the patch right into the corrugations
- Patching a very hot roof in full midday sun
- Stepping on rooflights or corroded sheets
Safety
Wear gloves and protective clothing, and only use Instapatch in a well-ventilated area. It contains polyester compound and styrene, which can irritate the eyes, skin and lungs. If it gets in your eyes, rinse them straight away with plenty of water and get medical advice. If it gets on your skin, wash it off with soap and water.
Storing spare patches
Keep unused patches on end in their original wrapping, somewhere cool, dry, dark and frost free. If a patch is very cold, warm it before use.