Q: What width do the sheets actually cover when lapped on the roof?
A: The 32/1000 Box Profile sheets cover 1 metre after lapping. The corrugated 13/3 sheeting covers 990mm after lapping.
Q: How much should each sheet be lapped?
A: Just 1 corrugation or profile on Box Profile sheeting. However, you may want to lap more corrugations or profiles on the last sheet of the run so the last sheet does not protrude over the end of the roof. It can be recommended with corrugated 13/3 sheeting to overlap by 1 and a half corrugations.
Q: When using TEK self drilling screws, do you fit them on the top or the lower part of the sheet profile?
A: For box profile and Tile form – The lower part. They have a neoprene washer below the screw head to prevent leaks and as long as the screws are fitted square, there should be no leaks. If the screws were fitted to the top of the profile the profile and sheet would distort as the screw is tightened.
For corrugated 13/3 you screw through the top of the corrugations, as due to the curve it cannot be distorted. Screwing into the top allows the washer to fully seal. If fitted in the gully it may block the flow.
Remember – do not overtighten or under tighten your screws as this can affect the performance of the washer and prevent it from sealing correctly. See diagram below.
Q: Is there any minimum order size?
Q: Do I need flashings?
A: Flashings are an integral part of any sheeted roof, covering the ridge where the two sides of a pent/single pitch roof meet, closing off the corners and ends of runs of sheets, creating an apron where a roof abuts a wall or sealing off reveals such as doors and windows. We stock a standard 90º corner or 130º ridge flashings in popular colours. Flashings are generally fitted directly to the high point of the profiled sheet using self-drilling stitching TEK screws that has a coarse thread that joins two pieces of sheet metal together. Flashings are available in standard 3m lengths. They should be fitted with a 150mm overlap.
If you require custom made flashings, please call our sales team on 01745 822 000.
Q: How Should I handle the sheets?
A: Care should be taken when handling sheets to prevent damage or injury. When handling sheets protective clothing such as gloves, steel toe capped boots and high visibility jackets should be worn to avoid accidents. Ideally mechanical handling equipment (e.g. a forklift truck) should be used where appropriate. Dragging one sheet’s edge across another may cause scratching of the sheet below so take care to lift and not drag sheets. Any packaging should be removed before lifting sheets onto a roof. Once on the roof and prior to fixing, sheets should be kept secured to the roof, close to the rafter line and, in so far as is possible, spread out so their weight is evenly distributed across the purlins. Any debris arising should be removed and off-cuts of insulation, surplus fasteners and similar not left on the sheeting.
Davies Bros accept no liability for any loss or injury caused by following the information in this guide. If you are unsure about how best to install your roof, we would recommend contacting an experienced professional.
Before handling any sheeting please visit the HSE website for further information on health and safety guidelines.
Q: What is the right type of sheet?
A: The type of sheet required will depend on the building type, use and appearance. Davies Bros manufactures and supply 4 different types of profiled sheeting, all of which can be supplied to the exact length necessary in a choice of colours, with the necessary roof lights, flashings, fixings, fillers etc
32/1000 Box Profile Sheeting
32/1000 box profiled sheeting is our most popular profile for either roof or wall cladding. This profile gives 1 metre width cover when lapped and can be made up to any length (for 0.7mm thickness) This single skin sheet due to its 6 rib 32mm deep profile sections can expel water quicker and can be used on roofs at minimum pitch of 4-5 degrees. It is fixed through the lower part of the profile to the purling using self-drilling TEK screws.
13/3 Corrugated Sheeting
13/3 corrugated sheeting gives a traditional look to either roof or wall cladding. Corrugated sheets give 990mm width cover when lapped and can be made up to 6 metre lengths. Corrugated sheeting is not as strong as 34/1000 box profile due to its smaller profile sections with this in mind you may need closer purlin supports. Corrugated sheeting can be used on roofs at minimum pitch of 10º.
Due to its curved shape it is fixed through the higher part of the profile to the purling using longer self drilling TEK screws.
33/1000 tile form roof sheet gives a roof a pan tiled appearance, giving 1 metre width cover when lapped and can be made up to any length. Tile sheet is considered not as strong as either 32/1000 box profile or corrugated 13/3 due to its stepped sections. These sheets require purlin spacings of 600mm centres. These sheets can be used on roofs with a minimum pitch of 12º. It is fixed through the lower part of the tile profile to the purling using self-drilling TEK screws.
Q: Care and Maintenance of my sheets?
A: Your new roof should be inspected at least yearly and cleaned of debris such as leaves to ensure a long useful life. Areas that have become marked may be cleaned using soap and water. More persistent marks may be addressed through the usage of white spirit or car paint cutting compound.