Description
WK-DS085 Spiral Anchor 10 pcs — 85 mm Helical Fastener for Insulation Facades
Product Overview
The WK-DS085 Spiral Anchor (10 pcs) is an 85 mm helical screw-in fastener manufactured by Klimas Wkręt-met, designed for attaching lightweight, non-structural elements to polystyrene insulation facades without creating a thermal bridge at the attachment point. The spiral thread grips the insulation board from within, distributing the load across the full anchor length rather than concentrating it at a single point, while the polyamide construction ensures the fixing does not conduct heat through the insulation layer. Each anchor supports items up to 5 kg — covering house numbers, signage, mailboxes, lighting fixtures, motion sensors, cable clips, and similar facade-mounted accessories. The 28 mm head accepts a TORX-30 drive bit and the anchor is installed using a standard cordless drill or screwdriver with no pre-drilling required in EPS insulation. Supplied in packs of 10 pieces, the WK-DS085 is part of the insulation fixing accessories range at Renders World.
Key Benefits
- Thermal-bridge-free attachment — the polyamide body has negligible thermal conductivity, so each anchor maintains the continuous insulation envelope at the attachment point rather than creating a conductive path through the insulation layer to the substrate behind.
- 85 mm length for standard domestic insulation thicknesses — the anchor grips securely within insulation boards of 80 mm and above, making it the correct length for the majority of UK domestic EWI retrofits where 80–100 mm EPS is the standard specification.
- 5 kg load capacity per anchor — sufficient for house numbers, signage, mailboxes, small lighting fixtures, motion sensors, cable clips, and similar lightweight facade accessories without over-stressing the insulation or anchor.
- TORX-30 drive for positive engagement — the 28 mm head accepts a TORX-30 bit, providing slip-free driving even at low drill speeds, reducing cam-out risk compared with Phillips or slotted drives.
- No pre-drilling required in EPS — the helical thread cuts its own path through expanded polystyrene, so the anchor installs directly with a drill or screwdriver in seconds without a pilot hole.
- Weather-resistant polyamide construction — the high-quality polyamide resists UV degradation, moisture, frost, and alkaline render chemistry, maintaining its structural integrity and grip throughout the service life of the insulation system.
Technical Specifications
| Property | Value |
|---|---|
| Designation | WK-DS085 |
| Manufacturer | Klimas Wkręt-met |
| Anchor length | 85 mm |
| Head diameter | 28 mm |
| Socket type | TORX-30 |
| Compatible screw diameter | 4.5 mm |
| Material | Polyamide |
| Maximum load per anchor | 5 kg (non-structural) |
| Compatible insulation | EPS (white and graphite), XPS |
| Suitable insulation thickness | 80 mm and above |
| Pack quantity | 10 pcs |
Application and Compatibility
The WK-DS085 is used after the EWI system is complete — insulation bonded and mechanically fixed, basecoat and mesh applied, and render finish cured — to attach lightweight accessories to the facade without penetrating through to the masonry substrate. The anchor screws directly into the EPS insulation board behind the render, and the helical thread distributes the suspended load across the full 85 mm engagement length. Because the anchor sits entirely within the insulation layer, it introduces no metal-to-masonry contact and therefore no thermal bridge.
Typical items mounted with spiral anchors include house numbers and name plates, small external mailboxes, PIR motion sensor units, external lighting brackets (within the 5 kg limit), cable clips and conduit supports, signage, and decorative facade accessories. Each anchor supports up to 5 kg in a static, non-dynamic load condition. Items that generate significant dynamic forces — shutters, blinds, window awnings, satellite dishes — require through-fixing to the structural substrate behind the insulation and are outside the scope of this product.
The 85 mm length is sized for insulation boards of 80 mm and above, covering the most common domestic EWI thicknesses. For thinner insulation — 30 mm to 50 mm reveal linings or soffit returns — the WK-DS050 50 mm spiral anchor provides the same fixing mechanism at a shorter engagement length suited to the thinner board.
Installation Notes
For the best result, mark the desired mounting position on the rendered facade surface. Fit a TORX-30 bit into a cordless drill or impact driver and set the tool to a low-to-moderate speed — approximately 400–800 rpm. Place the anchor tip against the render surface and drive it in steadily until the head sits flush with or fractionally below the render face. The helical thread cuts through the render, basecoat, and insulation in a single continuous action; no pre-drilling is required in EPS boards.
Once the anchor is seated, insert a 4.5 mm diameter screw (stainless steel recommended for external use) through the item being mounted and into the TORX-30 socket in the anchor head. Tighten the screw until the mounted item is secure against the facade surface without over-compressing the render at the fixing point. For items requiring multiple mounting points — such as a mailbox or lighting bracket — use one anchor per mounting hole and ensure all anchors are driven to the same depth for a level installation.
The insulation fixings installation guide covers the broader context of mechanical fixings within EWI systems, including how spiral anchors relate to the primary board fixings and when through-fixings to the substrate are required instead.
Installer's Note
Spiral anchors are the finishing touch that clients always ask about — they want to know how their house number, security light, and postbox go back on after the insulation is finished. The WK-DS085 answers that question cleanly: a 10-second installation per anchor, no drilling into the masonry behind, and no thermal bridge left in the insulation. The 85 mm length grips well in 80 mm and 100 mm EPS, which covers the bulk of domestic retrofit work. The one thing to watch is the 5 kg limit — it sounds generous, but a cast-iron house number with a metal backing plate or a heavy coach lantern can exceed it. Weigh the item before committing, and if it comes in over 5 kg, use a through-fixing with a thermal isolating sleeve to the substrate instead. Two anchors do not double the capacity to 10 kg in a meaningful way, because the insulation itself is the limiting factor, not just the anchor.
Is This Product Right for Your Project?
- Ideal for mounting lightweight accessories on insulated facades — choose the WK-DS085 spiral anchor for house numbers, small lighting fixtures, motion sensors, cable clips, mailboxes, and signage on EWI systems where the insulation is 80 mm or thicker and each item weighs no more than 5 kg.
- For thinner insulation (30–50 mm) — the WK-DS050 50 mm spiral anchor provides the same thermal-bridge-free fixing mechanism at a shorter length suited to reveal linings, soffit returns, and thin-board applications.
- For structural or heavy-duty facade fixings — items exceeding 5 kg or generating dynamic loads (shutters, awnings, satellite dishes) require through-fixings to the masonry or timber-frame substrate behind the insulation; browse the full insulation fixing accessories collection for heavier-duty solutions.
Frequently Asked Questions
Can I use the WK-DS085 on mineral wool insulation?
The helical thread is optimised for the cell structure of expanded polystyrene. In mineral wool, the thread may not develop the same grip because the fibrous matrix compresses rather than shearing cleanly around the helix. For mineral wool facades, a through-fixing with a thermal isolating sleeve to the substrate behind is the more reliable mounting method for facade accessories. Some installers report acceptable holding in high-density dual-density mineral wool slabs, but this should be verified with a pull test on site before committing items to the facade.
How close to the board edge can I install an anchor?
Maintain a minimum distance of 50 mm from any board edge or joint line. The helical thread needs a continuous volume of insulation around it to develop full grip; installing too close to an edge or joint risks splitting the board or reducing the pull-out resistance below the rated 5 kg capacity.
What is the difference between the 85 mm and 50 mm spiral anchors?
The difference is engagement length. The 85 mm anchor is designed for insulation boards of 80 mm and above — the standard thicknesses on domestic EWI retrofits. The 50 mm anchor suits thinner boards of 30–50 mm used in reveal linings, soffit returns, and junction detailing. Both share the same 28 mm head diameter, TORX-30 drive, polyamide construction, and 5 kg load rating.
Can I paint or render over the anchor head after installation?
Yes. The 28 mm polyamide head accepts render and paint finishes without adhesion issues. For the neatest result, apply a thin skim of basecoat over the seated head, allow it to cure, then touch up with the render finish to match the surrounding facade. The anchor head sits flush when correctly installed, so the touch-up blends into the surrounding texture with minimal visibility.