Radiator Boxing In

A good cover starts with a question, not a saw: will the radiator still heat the room once it is covered? Every cover holds back some heat. So the first step is to look at the type and size of the radiator and ask whether it already struggles. If the room is hard to keep warm in winter even without a cover, boxing it in will make things worse.

1. Assess the radiator: its type (panel, column or cast iron), size, position and heat output from the label or documentation, with a heating engineer if needed.
2. Measure the space: the height, width and depth of the radiator, the distance to the windowsill, floor and side walls, and where the valves and pipes are.
3. Design the cover: ventilation openings at the bottom and the top, access to the thermostatic valve head and the lockshield valve, and a removable section for cleaning.
4. Choose the material, depending on whether the cover should be permanent or easy to remove.
5. Build the frame or fit a ready-made cover.
6. Finish the surface: filling, sanding, painting or varnishing.
7. Run the heating and enlarge the openings if the room does not warm up properly.

Why do the openings need to be at both the bottom and the top? A radiator warms the air around it. Warm air rises and cooler air is drawn in from below. If the cover is open only at the front or only at the top, this natural flow breaks down and the heat stays trapped inside the box.

Plasterboard

Plasterboard suits situations where the radiator should disappear into the wall, for example as part of a false wall or an alcove. Boards are screwed to metal studs fixed to the wall and floor, then filled and painted together with the wall. This is a permanent solution. If the radiator is replaced later, part of the structure has to come apart. That is why plasterboard enclosures need ventilation grilles and an access panel.

Timber

A timber radiator cabinet fits well in traditional interiors and can be matched to furniture or flooring. It usually stands on its own or simply hangs on the wall, so it is easy to take off. The top board can work as a shelf. Solid wood does need plenty of ventilation and a finish that copes with long-term heat.

MDF

MDF can be cut precisely, and a decorative grille can be routed straight into it. It takes paint, lacquer or foil well. Choose a board and a finish that the manufacturer recommends for warm conditions, otherwise the cover may warp or turn yellow over time.

Metal

Perforated metal covers are sturdy, let heat through well and look modern. They are often made to measure, so preparation takes longer and fitting needs more precision.

How much work the job takes, and so what it ends up costing, depends on several things:

• The size of the radiator and how many there are, since several identical covers are quicker to make
• Position, as a cover under a window with a low sill or in a corner is harder to design
• How straight the walls and floor are, because uneven walls mean the frame has to be adjusted
• The material and how complex the design is, since curves, cut-outs and decorative details add work
• The finish, as varnishing or staining means extra steps
• Where the valves and pipes run, because awkward pipework means the cover has to be adapted

If you live in a flat, check whether your building uses heat cost allocators, the small meters fitted to each radiator. A covered radiator can affect their readings, so tell the building management or owners' association before you box it in and ask how they handle billing. A simple indoor cover is not normally building work that needs approval. If it is part of a larger renovation, check with your local building authority what the whole project requires.

• No ventilation. A cover without openings at the bottom and top traps heat, the room warms up more slowly and the heating runs longer.
• Thermostatic head inside the box. The valve head senses the warm air trapped under the cover and closes the valve before the room is warm. An opening right at the head helps, or a thermostatic head with a remote sensor.
• Unsuitable material. Cheap boards, plastics or finishes not meant for heat warp or change colour.
• Cover too tight to the radiator. There should be an air gap between the radiator and the cover. A box that is too deep and closed, on the other hand, creates a pocket of warm air.
• No access to the valves. When the radiator needs bleeding or repairing, the cover then has to be broken open or taken apart.
• Plasterboard without a proper frame. Boards simply glued to the wall, or poorly fixed studs, crack over time.

You can fit a ready-made timber, MDF or metal cover yourself. A plasterboard enclosure around the radiator, and any work on pipes or valves, is better left to a professional.

1. Switch off the heating or wait until the radiator has cooled down.
2. Measure the width, height and depth of the radiator, including the valves and the thermostatic head.
3. Choose a cover that is a few centimetres larger than the radiator on every side and has ventilation at the bottom and the top.
4. Check that you can reach the thermostatic head through an opening or a removable section.
5. Vacuum the dust from the radiator and underneath it while it is still easy to reach.
6. Fit the cover following the manufacturer's instructions, and fix wall-hung types to the wall with suitable plugs.
7. Make sure the cover is stable and does not touch the pipes or valves.
8. Switch the heating back on and after a few hours check that the room warms up as it did before.

• The cover is firmly fixed and does not move when you push it
• There are ventilation openings at the bottom and the top, and nothing blocks them
• The thermostatic head and the lockshield valve can be reached without taking anything apart
• The removable section or access panel opens easily
• There is an air gap between the cover and the radiator
• The surface is smooth, with no cracks or sharp edges
• The cover does not warp or give off a smell once the heating is on
• The room heats up about as well as it did before the radiator was covered