EPS Plug Caps, Grey Graphite Polystyrene, 100 per Pack

These EPS plug caps are grey graphite polystyrene discs, sold 100 to a pack, for closing the hole left when the head of an insulation plug is sunk into a polystyrene board. Renders World stocks them in the insulation fixings range, beside the plugs, discs and the cutter that makes the hole the caps fill.

What Is in a Pack of EPS Plug Caps

One pack holds 100 caps. The shop photograph shows round caps of grey expanded polystyrene with the bead structure visible on the face and the edge, each a short cylinder rather than a flat washer, and a box full of the same caps behind them. Renders World listed the same goods before as a disc cap for EPS boards in graphite, and graphite is the colour the caps are sold in today.

• Material — expanded polystyrene, grey, as the photograph and the product name show.
• Quantity — 100 caps per pack, the figure in the product's own name.
• Barcode — 5902143663171 on the listing, the number to look for on the label when the pack arrives.
• Not stated on the listing — diameter, thickness, density or grade of the polystyrene, and the maker's name.

Where the Caps Go in the Fixing Stage

A plug driven flush leaves its plate on the face of the insulation. A plug driven deeper, with its head sunk in, leaves a round hole above the plate instead, and the cap is the piece of polystyrene that goes back into that hole so the insulation face is whole again before the basecoat and mesh go on. Each recessed fixing takes three moves:

1. Drive the plug through the insulation into the wall.
2. Cut the recess over its head with a countersinking cutter.
3. Press in the cap, level with the surrounding face.

The order of the whole fixing stage, from the first course to the walk-round before basecoat, is set out in the guide to installing insulation fixings.

How Many Packs of Plug Caps to Order

A cap is needed for every plug whose head is sunk in, so the count of caps is the count of recessed plugs, not a figure per square metre. Count the plugs from the fixing layout, then divide by 100 and round up.

• LTX plugs in boxes of 200 — the 70 mm to 200 mm LTX polystyrene fixing plugs on the shelf come 200 to a box, so one full box of recessed plugs takes two packs of caps.
• LTX plugs in boxes of 100 — the 220 mm LTX plug comes 100 to a box, which is one pack of caps per box.
• Plugs left flush — need no cap, so only the recessed ones count.

How many plugs go into each sheet of insulation, and where they sit across the field and at the edges, is a system figure rather than a rule of thumb. The fixing pattern and spacing guide covers how that layout is set.

What to Check Before a Large Order

The listing gives no diameter and no thickness for these plug caps, and the maker's product table for the cutter on the shelf names no recess size either. Fit is therefore settled on one fixing, before a whole elevation is cut:

1. Cut one recess with the cutter that will be used on the job.
2. Press one cap in and lay a straight edge across it: a cap level with the surrounding face is the right fit, one that rattles in the hole or stands proud is not.
3. Ring Renders World before ordering for a full building if the cap's diameter and thickness are needed in figures, or a match to a particular cutter.

Grey Caps on Graphite Insulation

The caps are grey, like the graphite polystyrene boards in the EPS board range, so a capped fixing reads as part of the wall rather than as a white spot on a grey face.

• What the colour tells you — the caps are sold in graphite grey, the colour of the graphite boards, and blend with them once pressed in.
• What it does not — the listing says nothing about the polystyrene grade of the caps, so they are bought as a filler for the recess, not as a match for the insulation figures of the boards.

Questions Before Ordering EPS Plug Caps

What size are the caps?

The listing does not state a diameter or a thickness, and nothing is printed on the caps in the photograph. Test one cap in a recess cut with your cutter, or ring the shop before a large order if you need the figures.

How many packs go with a box of LTX plugs?

Two packs for a box of 200 plugs, one pack for a box of 100, counting only the plugs sunk into the insulation. Plugs left flush are not capped.

Do they fit the cutter sold here?

Neither listing gives the sizes that would answer that on paper, which is why the one-cap test on the first recess is the check to make. A cap that goes in level with the surrounding face is the right fit.

Are they for mineral wool slabs as well?

These are polystyrene caps, sold for polystyrene boards, which is how the shop has listed them under both their old and their current name. The listing does not cover wool slabs, so a wool build-up is a question to settle with the system before ordering.