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Washers & Covers
washers-covers
Washers and Covers for Trade and DIY
A missing washer can ruin a perfectly good fixing. It causes surface damage, loosens over time, and fails under load. This range of washers and covers keeps your fixings safe and secure. You will find TIMCO washers, SELA washers, repair washers, mudguard washers, and finishing covers. All sizes and materials are stocked for trade and DIY use across the UK. Whether you are on site or at home, the right washer is here.
Why Washers and Covers Matter on Every Job
Washers do more than most people think. They spread load across a wider surface area. This stops bolts and screws from pulling through soft materials.
Without a washer, a bolt head can dig in and crack the surface. It can also work loose due to vibration over time. A washer protects both the fixing and the material being fixed.
Covers and caps give a clean, finished look. They hide screw heads and protect fixings from moisture and dust. They are popular in furniture assembly, decking, and outdoor structures.
Quick tip: Always match the washer outer diameter to the bolt or screw head size. A washer that is too small offers very little load spread. A washer that is too large may not fit the recess or countersink.
Types of Washers and Covers Available
Different jobs need different washers. Here is a plain guide to the types stocked and what each one does.
Flat Washers (Form A)
Flat washers are the most common type used in the UK. They sit under a nut or bolt head to spread the load. Form A washers have a standard outer diameter. They are used in timber, steel, and general construction work. Available in zinc plated and stainless steel finishes.
Repair Washers
Repair washers have a very large outer diameter. This makes them ideal for repairing oversized or damaged holes. They cover and reinforce holes that have been stripped or widened. Commonly used in roofing, fencing, and sheet material repairs. A practical fix for holes that have become too large.
Mudguard Washers
Mudguard washers have a wide diameter relative to the centre hole. They give a large bearing surface on thin or soft materials. Originally used in vehicle mudguard fixings. Now used widely in sheet metal, plastic panels, and cladding work. Available in a range of diameters and finishes.
Penny Washers
Penny washers are very similar to mudguard washers. They have a wider face than standard flat washers. Used where the fixing needs extra bearing surface on soft material. Popular in insulation board fixing and timber cladding work. A simple, low-cost way to prevent pull-through.
SELA Washers
SELA washers are specialist sealing washers. They combine a metal washer with a rubber or EPDM sealing layer. This seals the fixing point against water ingress. Used widely in roofing sheet fixings and corrugated panel work. Essential where a watertight seal is required around the screw.
Screw Cups and Covers
Screw cups sit around the head of a countersunk screw. They give a neat, decorative finish to visible screw heads. Covers snap over screw heads to hide them completely. Both are used in furniture, joinery, and interior woodwork. Available in chrome, brass, and white finishes.
Spring Washers
Spring washers add tension beneath a nut or bolt head. This helps resist loosening caused by vibration. They are used in mechanical assemblies and structural bolted joints. Not for soft surfaces where a flat washer is needed instead. Square section and single coil types are both available.
Finishing Caps and Push-On Covers
Push-on caps fit over bolt ends or screw heads. They protect the fixing and give a smooth, safe finish. Used on exposed bolt ends in furniture and outdoor structures. Prevent sharp edges from causing injury. Available in plastic in several sizes and colours.
TIMCO Washers and SELA Washers at JALFT
TIMCO is a leading UK supplier of fixings and fasteners. TIMCO washers are made to reliable standards for trade use. They are packed in sensible quantities for site and workshop use.
SELA washers are a well-known product in the roofing trade. The SELA washer uses a bonded sealing layer under the metal face. This creates a seal around the fixing point when tightened. It stops rainwater getting in through the fixing hole.
Both brands are trusted by tradespeople across the UK. You will find TIMCO and SELA products throughout this range.
Note: SELA washers are used specifically with self-drilling roofing screws. Always pair the correct washer diameter with the roofing sheet profile being fixed. Using the wrong size leaves gaps and allows water in.
Which Washer Is Right for Your Job?
The right washer depends on the material, the load, and the environment. Here is a simple guide to help you decide.
Fixing Into Timber
Use a flat Form A washer under bolts or coach screws. For soft timber or sheet material, use a mudguard or penny washer. This prevents the fixing pulling through under load.
Roofing Sheet Work
Always use SELA washers with roofing screws. The rubber seal on the SELA washer keeps water out. Do not use standard flat washers for roofing sheet fixings.
Repairing Damaged Holes
Repair washers are built for this exact task. Their oversized face covers and bridges the damaged area. They restore clamping strength without replacing the whole sheet.
Bolted Structural Joints
Use flat washers under both the nut and bolt head. Add a spring washer under the nut if vibration is a concern. Always check the required washer size for the bolt diameter.
Neat Indoor Finishes
Use screw cups or snap-on covers to hide screw heads. These are ideal for furniture, joinery, and interior fitting work. They give a professional, tidy result on visible fixings.
Outdoor and Exposed Fixings
Use stainless steel or hot-dipped galvanised washers outside. Zinc-plated washers will corrode in wet UK conditions. Pair with the correct grade of outdoor screw or bolt.
Washer Materials and Finishes Explained
The finish on your washer affects how long it lasts. Picking the wrong finish in the wrong setting leads to rust and failure.
| Finish / Material | Best Environment | Common Use |
|---|---|---|
| Zinc Plated Steel | Dry, internal settings | General indoor construction, furniture, joinery |
| Hot-Dipped Galvanised | Outdoor, intermittent wet | Fencing, external frames, outdoor structures |
| A2 Stainless Steel | Outdoor and damp areas | External cladding, decking, garden buildings |
| A4 Stainless Steel | Coastal or chemical exposure | Marine, poolside, and industrial environments |
| EPDM Bonded (SELA) | Roofing and waterproofing | Roofing sheet screws, corrugated panel fixing |
| Plastic / Nylon | Electrical or decorative use | Screw caps, covers, and insulating applications |
In the UK, outdoor fixings are exposed to regular rain. Always use at least hot-dipped galvanised washers for any external work. Stainless steel gives the longest service life in harsh conditions.
Get the Right Washer or Cover for Your Project
Use the filters above to narrow by type, size, and finish. Check individual product pages for exact dimensions before ordering.
This range covers flat washers, repair washers, mudguard washers, penny washers, SELA washers, spring washers, screw cups, and finishing covers. You will also find TIMCO washers in practical pack sizes for trade use. For help matching washers to the right screws or bolts, see our nuts, bolts, and washers range or our roofing screws if you need washers for sheet roof fixing.
Frequently Asked Questions
What is a washer used for in fixings?
A washer sits under a bolt head or nut to spread the clamping load. It stops the fixing digging into the surface and protects the material. It also helps prevent the fixing from working loose over time.
What is a SELA washer?
A SELA washer is a metal washer with a bonded rubber or EPDM sealing layer. It creates a watertight seal around the fixing hole when tightened. SELA washers are used with self-drilling screws in roofing sheet work.
What is the difference between a mudguard washer and a flat washer?
A mudguard washer has a much larger outer diameter than a standard flat washer. This gives a bigger bearing surface on thin or soft materials. Flat washers are for general use where the material is hard enough to resist pull-through.
What are repair washers used for?
Repair washers are used to cover holes that have become too large for the original fixing. Their oversized face bridges the damaged area and restores clamping strength. They are commonly used in roofing, fencing, and sheet panel repairs.
Can I use zinc-plated washers outside?
Zinc-plated washers are not recommended for outdoor use in the UK. They will corrode in damp and wet conditions. Use hot-dipped galvanised or stainless steel washers for external fixings.
What is a screw cup used for?
A screw cup sits around the head of a countersunk screw. It gives a neat, decorative finish to the fixing on visible surfaces. Screw cups are commonly used in furniture, cabinet making, and joinery.
Do TIMCO washers come in packs?
Yes. TIMCO washers are available in practical trade pack sizes. Pack quantities vary by size and type. Check each product listing for the exact pack size before ordering.
Related Fixings and Fasteners
Washers are often used alongside bolts, screws, and nuts. See our nuts, bolts, and washers range for complete fastener sets.
For roofing applications, SELA washers work alongside self-drilling screws. See our roofing screws for the correct pairing.