If you suffer from a cold house, it may not be your heating system that is at fault. Vast amounts of heat can be lost through walls, windows and the roof but don’t despair help is at hand in the form of the many different types of insulating materials that are available.
The benefits of insulation
Heat escapes from nearly every part of a house – roof, walls, windows, doors, even the floor – adding substantial amounts to your fuel costs. Insulating the major problem areas can make a great deal of difference to your comfort and your costs.
Draughtproofing openings like windows and doors is simple, cheap and effective. But walls, roofs and floors can account for far greater losses of 35% wall heat because of their large area. The figures below illustrate the difference that good insulation can make. Roofs are always a major culprit but they are areas where you can dramatically reduce the loss without spending a great deal of money or causing an unnecessary upheaval.
Walls, especially older solid external walls, lose an even greater amount and can frequently cause condensation on the inside too. Together these two areas lose more heat than all the others.
Heat loss from an uninsulated house
25% roof
35% wall
15% door
15% floor
10% window
Heat loss from an insulated house
8% roof
12% wall
9% door
9% floor
5% window
Insulating floors
Surprisingly enough, the heat loss from a floor area can be quite considerable so cutting it down is a worthwhile job.
Floor boards: With a wooden floor, check for gaps between the boards. Small ones can be filled with the appropriate mastic. For larger gaps cut tapered wooden wedges’ to fit, coating both sides with PVA adhesive before placing each wedge between the boards and tapping gently to get a snug fit. Any projecting edges should be planed off flush with the other boards.
Holes in floorboards where old pipes or wire came in can be patched with pieces of wood, but larger ones are best dealt with by removing the relevant section of board and replacing it with a new piece cut to fit.
Skirtings: If the floor and the skirting don’t quite meet, fill in with a wooden moulding pinned and glued into position. Pin to the floor, not the skirting.
Concrete floors: Insulation has been made simple with systems of interlocking panels, available separately or bonded to a finishing material. The panels are laid loose and neatly connected or ‘clicked’ together by plastic inserts. For floors buy the chipboard finish or cover the panels with a separate ‘floating’ layer of flooring grade chipboard.
It’s important to first check if the floor is damp and if it is coated with a waterproof agent.
Level out any uneven patches with a self-levelling screed. Remove any doors in the room, later you will cut them to match the higher floor level. Prise off existing skirting boards and replace them later. Lay the boards straight onto the concrete, working from one corner of the room and begin to alternate rows with panels cut in half to get a ‘brickwork’ effect for extra strength. Before butting the panels together with the inter locking inserts, coat the edges with PVA adhesive to give extra bonding and rigidity. Finally, cover unbonded panels with a continuous layer of flooring grade chipboard. Refix door and skirtings at their new height. Where changes in floor level occur, cut a strip of board to form the rise and fit together to ensure continuous insulation.
Dealing with solid walls
Cavity wall insulation is a job for the professional. But when it comes to solid external walls which let a lot of heat escape, DIY insulation is a practical solution.
Lining the wall with polystyrene in 5mm roll form is cheap and simple, but although it reduces condensation, it won’t cut the heat loss dramatically. But other similar methods can do so very effectively.
Dry lining: Boards and battens have largely been superseded by various thermal boards which fix directly to the wall. Gyproc thermal board, for example, is attached to the wall with 863 Gyproc adhesive and comes in standard 1200mm widths, three lengths and several thicknesses of insulation.
1. To use Gyproc thermal board, first remove wallpaper or sand down paintwork with a coarse grade paper then brush off any dust. Remove any skirtings and anything else attached to the wall surface.
2. Alternatively, fix the boards directly above existing skirtings by removing a section of polystyrene backing. Apply in the following way before attaching new skirting boards to the wall lining.
Light and plug sockets will have to be relocated to accommodate the new lining and wooden window sills should be extended to accommodate the thickness of the wall board. If the existing sill has a curved edge, plane it square and glue and pin a new piece of wood to the edge.
Next draw out the board sections on the wall. Start from a door or window and remember to allow for the thickness of the board which will line the window or door recess. Add 2mm to the overlap to allow for the thickness of the adhesive.
Cut the boards to size with the wallboard surface uppermost. Use a fine tooth saw to cut at a shallow angle.
Mark the first board at nine points for the secondary fittings. These should be marked in three rows of three across the top, middle and bottom of the board in portrait position. Lay the board on the floor and place a spare piece of wood under the board to prevent damage to the floor surface from the drill bit, before drilling for screws or nailable plugs. Use either method to fix boards to the old wall surface.
Put the board against the wall and get someone to hold it in position while you mark the fixing points on the wall through the drill holes. Take the board away and drill the holes in the wall using a masonry bit if you intend to use screws. Now cut sections out of the board for switches or sockets.
Apply adhesive to the wall in bands 200mm wide as shown on the diagram with a trowel. Spread with an applicator.
Place the board in its position against the marked wall, making sure the vertical edge is plumb and tamp it firmly into place. Put in the secondary fixings, either nailable plugs or screws.
The sides of the window and door recesses should also be lined with the board. If the exposed framework of the window or door is not wide enough to accommodate the thickness of the board, the existing plaster should be removed from the recess and the background thoroughly cleaned. It will be necessary to remove the polystyrene from the wall panel where it overlaps the recess in order to allow the plaster edges to meet. Fix the lining with adhesive and provide support for the top piece for 24 hours to allow it to dry.
When all the boards are in position, fill in between the joins with a joint filler – fill the screw heads too. The method is the same as that used for jointing ordinary taper edged plasterboard. Use jointing tape to cover the filled joints.
Reveals need special attention. Remove the thermal backing so that you can overlap the boards. About an hour after applying the filler and tape, apply Gyproc joint finish, stir 5kg into two litres of cold water or amounts in the same proportions, spread in a broad 200mm wide band down the joint, feathering out the edges slightly with a damp sponge or cloth.
To finish the job apply a coat of drywall topcoat over the boards and refix the skirting.
Insulating the loft
The job of laying loft insulation is not a difficult one and it provides very worthwhile savings in fuel costs.
Preparation
Apart from clearing the loft of anything you have stored there, little preparation work is necessary. However, this is the time to tackle repairs you’ve been putting off such as closing any roof tile gaps, which could later expand, let in water and cause a build up of damp in the insulation. Seal any holes where birds or vermin can enter, especially at eaves and gutters. But do not cut off all ventilation because this can encourage dry rot. Cover ventilation gaps with a fine wire mesh to keep birds out.
Inspecting timbers for woodworm is also worthwhile at this stage. Access to joists will be difficult after the insulation is laid, and if there is any woodworm present, any insulation must be removed to treat it.
For ease and safety, make a platform to work from by laying a number of boards across three or four ceiling joists, moving them as you go.
Insulation materials
There are a variety of loft insulation products. Prices vary so check to see which is the best buy.
Blanket: Made either of glass fibre or mineral wool, this comes in rolls wide enough to fit into the 350mm to 400mm spacing between joists.
Various thicknesses are available; the thicker the material. the better the heat retaining properties. Regard 75mm as the absolute minimum.
To lay blanket insulation. you just place the roll between the joists and unroll it. Wear gloves, goggles and a dust mask to prevent irritation and be careful not to compress the material as you work. Cut at the end of one run and start again. Lay under pipes and wire for easy access to them later should you ever require it. When you get to the eaves or other awkward areas, a long handled brush may help push the material in.
Don’t insulate beneath your cold water tank.
One tip is to put insulation on the loft side of the trap door. Cut a piece of insulation to fit and cover it with polythene.
Quilt: This is wider than the rolls and in the same materials. It’s intended to be draped over joists and because it traps a layer of air between itself and the ceiling below, it has better heat retaining qualities.
The disadvantage of quilt insulation is that it can cause access problems later and you will also need to make ‘walkways’ of boards screwed to joists above the quilt.
Foil: With a reflective face comes in quilt form for laying over joists, but used on its own it is not as effective as the other materials mentioned.
Loose fill: Some people find this the easiest insulating material of all to work with. You buy loose pellets or pieces of vermiculite or mineral fibre by the bag and simply tip them straight into the spaces between the joists. Aim for a depth of 100mm and, to get it level, make up a spreader from a piece of board. Incidentally, if your joists are more widely spaced than normal you can use a combination of blanket and loose fill – use the loose material to fill the gap.
Some of the materials can cause irritation to skin, nose and eyes, so be safe while you work by wearing a mask, gloves and goggles.
Tanks and Pipes
The best place to start this insulation project is the loft. Cold water tank: Make sure the pipe joints are in good order. If the ball valve needs changing (or its washer), now’s the time to do it. Check that the overflow works as it should. And finally, if your tank doesn’t already have a cover, make one from chipboard cut to size.
Take some blanket insulation and lay pieces over the top of the tank so that they overhang the sides. Then wrap more pieces right round all four sides of the tank, enclosing the top overhangs and overlapping at the join. Secure with string. The ‘cover’ should go to the floor but not under the tank.
Alternatively, build a lightweight structure around the tank with plywood and battens and then fill the space between box and tank with loosefill.
A third method is one which allows easiest access to the tank later and it’s also the simplest. Using block polystyrene of the correct size, build a container closely round the cistern. Hold the corner joints with plastic adhesive tape.
Pipes: Lagging these with pipe wrap is probably the cheapest way of doing the job. Just wrap the felt like material allowing a good overlap. Secure this with fine wire twists.
An alternative method is easier, but more costly. Buy purpose made sections of flexible foam plastic tube with a slit along one side for fitting over the pipe. Tape at intervals to secure the edges together and also tape the joins.
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