Picture Hook

Having designed a plasterboard fixing capable of withstanding high load factors, we thought the next logical step would be to design a picture hook to work in perfect harmony.

These hooks (roundels) are particularly effective when used as horizontally opposed pairs for hanging large, heavy items such as mirrors. Conventional hooks are not designed to work in pairs as they are not optimised to work with the lateral forces that are generated when more than one fixing is deployed – they skew from their vertical position, which can be problematic. Our hook can connect directly to the plasterboard as there is no protruding front flange from the fixing itself. This is highly advantageous due to the extended surface area in contact with the plasterboard, which produces a strengthening “sandwiching” effect on the plasterboard and also gives us the opportunity to utilise a locating ring to assist with installation. Orientation issues are permanently removed. Unlike conventional hooks, the central fixing bolt resides underneath the picture wire, which acts as a further failsafe.

The Hook from Grapplefix has some distinct advantages over conventional (hook-shaped) hooks, summarised below:

  1. Ease of installation, which takes seconds. The raised locating ring on the rear face of the hook is placed directly into the plasterboard hole after the Grapplefix has been inserted
  2. Due to the circular shape of the hook, there are no alignment issues – orientation simply doesn’t matter!
  3. The central, single fastener (bolt) is below the wire, which acts as a possible failsafe mechanism – most hooks attach above the wire
  4. The picture wire itself is not subjected to as much stress as it passes over the smooth circular inner groove of the hook. Importantly, the wire is not subjected to sharp bends or creases, which create areas of stress as they pass over the small looped ends of conventional metal hooks, which are sometimes only a couple of millimetres wide
  5. The hook only extends 9 mm from the face of the plasterboard (the bolt head is completely recessed), which is less than even some of the smaller conventional hooks. This greatly assists in achieving a cosmetically pleasing flush finish where required
  1. Increased load capacity. The large circular boss of the Grapplefix and the locating ring of the hook sit in the plasterboard hole preventing the tear through effects that traditional small diameter fixings suffer from. Additionally, the plasterboard is effectively sandwiched between the back plate of the Grapplefix and the large surface area of the rear face of the hook. Importantly these two surface areas are approximately equivalent. This has the added bonus of strengthening the plasterboard itself, which is often the weakest part of the installation. The high forces generated by the central fastener also create high friction between the hook and the plasterboard
  2. When a picture is hung from the hook, the force acting downwards on the hook acts to try to angle the fastener downwards, which in turn increases the tension in the fastener. However, this increases the friction of the rear face of the hook against the plasterboard, thus resisting the action of the force on the fastener and making the hook more resilient to heavier loads – the greater the load, the more effective it becomes
  3. For larger, heavier pictures or mirrors, hooks can be used in pairs set horizontally apart. The circular inner groove extending around each hook spreads out the load of the item (through the wire) on the hooks as the wire can pass around as much of each hook as required. Owing to the rotationally symmetric continuous groove of each hook, the resultant force from the wire is always radial to the central fastener (assuming a constant tension in the wire), which means that the hook would not rotate even if the central fastener were to become loose, as there is no resultant moment applied to the hook. Conventional hooks cannot do this as lateral forces create a moment that displaces them immediately from the vertical

A Note on Picture Wires

The hook works equally well for smaller, lighter loads, but when hanging significant loads (above 10 Kg), we recommend using a 7 x 7 (49 individual strands) 1.5 mm stainless steel wire, preferably PVC coated to reduce fraying (total diameter 2 mm).

The breaking strain of this type of wire is usually around 140 Kg (check the specification prior to installation). It is made up of 7 bundles, each containing 7 strands. This configuration gives the wire the required flexibility.

Other wire configurations such as 7 x 19 are even more flexible (therefore allowing for increased diameters) and a 2 mm, 7 x 19 uncoated stainless steel wire would give a breaking strain up to 230 Kg where extra safety multiples are required. Again, check the specification carefully prior to installation.

It should be noted that the picture hook slot is limited to wires (including any additional coating) of 3 mm (maximum) diameter.

Optimally, the ends of the wire should be as close to vertical as possible (with the two hooks positioned horizontally apart as far as possible), as this represents the configuration with the lowest resulting tension in the wire. However, this may not always be practical and is an optional configuration. The ends of the wire may diverge (as shown below – the less the better), be almost vertical (preferred) or even converge if required.

We are here to help with any questions you may have about our products or queries regarding this website. We can be contacted by email or phone. Please note you cannot purchase products directly from us either over the phone or via this website.

Email: enquiries@grapplefix.com

Phone: 0203 409 9000 or 0333 123 0450 (Free from mobiles)

Opening hours: Monday to Friday, 9 am to 5 pm

Registered Address:

Harwood House
43 Harwood Road
London
SW6 4QP

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