Metal-backed EPDM rubber washers designed for use with roofing tek screws. The 29mm diameter creates a reliable weatherproof seal around the fixings point. Available in 5.5mm and 6.3mm sizes. Bag of 100.
The 29mm washer roofing screw is only as good as its seal. If water finds its way past the fixing point, it will — and a failed or missing washer is usually where it starts. These EPDM-backed metal washers are designed specifically for roofing tek screws, combining a steel top plate with a vulcanised rubber underside to compress evenly around the penetration point and keep moisture out where it counts.
EPDM rubber is the material of choice for exterior roofing applications. It handles UV exposure, temperature cycling, and prolonged weathering without cracking or shrinking away from the metal, which is exactly the kind of long-term behaviour you want on a standing seam, corrugated steel, or box profile sheet. The 29mm diameter gives good coverage across the fixing head, spreading the load and giving the rubber enough contact area to form a proper compression seal.
Where These 29mm EPDM Washers Are Used
These are used anywhere a tek or self-drilling screw is driven through sheet roofing material into purlins or structural steelwork below. Agricultural buildings, industrial units, portal frame structures, and commercial re-roofing jobs all use washered roofing screws as standard. The washers are available in two shank sizes — 5.5mm and 6.3mm — to match the most commonly used roofing tek screw diameters on site.
Choosing the Right Size
Match the washer to the shank diameter of your screw. The 5.5mm version suits standard roofing teks used on lighter gauge sheeting, while the 6.3mm is the one to reach for when fixing into heavier structural sections or thicker sheet profiles where a beefier screw is specified. Getting this wrong means the washer will either spin freely or bind before it compresses properly, neither of which gives you a reliable seal.
Supplied in bags of 100, these washers are sensibly priced for the volume of fixings a roofing job typically demands. A bag goes quickly when you are running screws all day, so having a good stock on hand avoids that particularly annoying mid-roof situation where you have run out of one size and the merchant is shut.
Pro Tip: Always run the screw in until the EPDM rubber just starts to bulge outward around the washer edge — overtightening crushes the rubber and breaks the seal, undertightening leaves a gap that lets water track down the shank.
These EPDM washers are used wherever roofing tek screws penetrate metal sheet profiles on agricultural, industrial, and commercial buildings. They are standard on corrugated steel, box profile, and standing seam roofing systems fixed to steel purlins or structural framework. Roofers fitting new sheeting and contractors carrying out re-roofing or repair work will go through these by the hundred on a single job.
Best For
Box profile and corrugated metal roofing
Agricultural and industrial building roofing
Commercial re-roofing and repair work
Steel purlin and structural steel fixing
Compatible With
5.5mm shank roofing tek screws
6.3mm shank roofing tek screws
Self-drilling roofing fasteners
Steel and aluminium sheet profiles
Key Features
29mm diameter EPDM-backed metal washer
UV and weather resistant rubber compound
Compression seal around fixing penetration
Available in 5.5mm and 6.3mm shank sizes
100 per bag
Not suitable for: Not suitable for use with timber fixing screws or fasteners with shanks outside the 5.5mm and 6.3mm sizes listed. These are not designed for flat roofing membranes or applications requiring a chemical bond between the washer and sheet surface.
Fit each washer onto the screw shank before driving. Drive the screw until the rubber face makes full contact with the sheet and just begins to compress visibly at the edges. The washer should sit flat with the EPDM in even contact all around — no rocking, no gap on one side.
If the washer spins without compressing or seats at an angle, back the screw out and check that the correct size washer is being used for that screw shank. A washer that is too loose on the shank will not seal reliably regardless of how far the screw is driven.
Select the correct washer size to match your roofing tek screw shank diameter, either 5.5mm or 6.3mm.
Thread the washer onto the screw shank with the rubber face pointing toward the sheet surface.
Position the screw at the correct fixing point on the sheet, typically at the crest of the profile for weathertightness.
Drive the screw using a suitable hex-head driver bit at a steady, controlled speed.
Stop driving when the EPDM rubber makes full contact with the sheet and just begins to compress around the washer perimeter.
Check the washer is sitting flat with even contact all the way round before moving to the next fixing.
What is the difference between the 5.5mm and 6.3mm washer sizes?
The size refers to the internal hole diameter, which must match the shank of your roofing tek screw. The 5.5mm washers suit standard lighter-duty roofing screws, while the 6.3mm washers are for the larger diameter screws used on heavier gauge sheeting or structural fixing into thicker steel sections. Check your screw specification before ordering.
Why use EPDM rather than a plain rubber washer?
EPDM holds up to UV radiation and wide temperature swings far better than standard rubber, which can harden and crack over time when exposed to outdoor conditions. On a roof that sees direct sun in summer and freezing temperatures in winter, a plain rubber washer can fail within a few years. EPDM is the right material for long-term weatherproof performance in this application.
Each washer consists of a steel top plate bonded to an EPDM rubber compound underside. EPDM offers good resistance to UV degradation, ozone, and temperature extremes, making it a practical choice for exposed roofing applications. The 29mm outer diameter is the industry standard size for use with the most common roofing tek screw head profiles, available here in 5.5mm and 6.3mm internal diameters.
Washer Outer Diameter
29mm
Available Shank Sizes
5.5mm, 6.3mm
Washer Material
Steel with EPDM rubber backing
Pack Quantity
100
Application
Metal sheet roofing with tek screws
SKU
WA29
Size
5.5mm, 6.3mm
Box Quantity
100
Reviews
There are no reviews yet.
Be the first to review “Roofing Screw EPDM 29mm Washer – Bag 100”Cancel Reply
Reviews
There are no reviews yet.