Builders in London

Builders in London

Sound insulation

Installing a good quality double glazing system will give a substantial reduction in the decibel level of noise permeating through windows from typical town traffic or a local playground. However, if your noise problem is more acute, noise prevention is a more extensive technical matter – the actual source of the noise, the location of the house, the type of glass thickness needed, the distance the two panes are set apart and any additional insulation around windows or between the double glazing should all be considered. Professional advice should be sought from a quality double glazing company or building company on other methods of sound insulation.

noise loud

Government grants to install double glazing can be given to people living in certain heavy traffic areas or where there is an airport nearby. Your local authority will be able to supply details and advice. In normal noise level situations the two sheets of glass in a double glazing system should be at least l00mm apart to provide adequate sound insulation. To provide effective thermal insulation, the optimum gap should be of 20mm. If you want both sound and thermal insulation, you should select a wider gap or use triple glazing ; you will find thermal insulation is not greatly reduced in this case.

Double glazing

robuild installing double glazing patio door
While heat losses vary depending on the nature of a building and its aspect, in a typical uninsulated house about l5 percent of house heat is lost through the windows. If all the windows in such a house are double-glazed, this heat loss will be halved to give a seven and a half percent saving on fuel bills. There are many factors which can affect this figure – for example, the type of system used and how well it is fitted. Installing double glazing in an old cottage with just a few small windows would not obtain this saving whereas there will be higher savings in a modern ‘goldfish bowl’ type of property.

Double glazing is not a money saver on the scale of other forms of insulation such as glass fibre laid in the loft or cavity wall infill; however, there are a number of reasons why you will find the necessary expenditure worthwhile to add to the comfort of your home. An efficient system will eliminate cold, draughty areas round window making the whole floor area of a room usable on cold days, and rooms will seem larger without the need for occupants to cluster round the fire or radiators.

Preventing condensation
dirty double glazing
When rooms are properly heated and ventilated, condensation will be reduced and possibly eliminated by double-glazed windows, since the inner panes of glass will be warmer and less susceptible to misting. With some double glazing systems, interpane misting may occur; this is usually slight and can be wiped away provided the new window is hinged or sliding. Alternatively you can place silica gel crystals between the panes of glass; these absorb moisture and, when saturated, should be temporarily removed and dried in a warm oven.

Misting on the room side of the window indicates the temperature of the glass is too low, given the water content of the room’s atmosphere; by a process of trial and error, you should carry out adjustment until there is a proper balance between heat and ventilation in the room. Condensation on the cavity surface of the outer glass is usually a sign that moist air is leaking into the cavity from the room. Make the seal round the new double glazing as airtight as possible, using a tape form of draught excluder, and seal any gaps in the joints of a timber framework with a matching wood filler, making sure the filler penetrates through to the full depth of the joint. If this fails to cure the problem, drill ventilation holes through the primary frame to the drier air outside. In a 1m wide window, two 10mm diameter holes set 500mm apart should be sufficient.

More will be needed for larger windows; you can decide the exact number by a process of trial and error – drilling an extra hole and waiting to see if this cures the problem. Pack the holes with glass fibre to act as an air filter. With hermetically sealed units the air in the cavity is dried, so condensation between the panes is not possible as long as the seals remain sound; failure of the seals is a rare occurrence, but reputable manufacturers give long-term guarantees to cover the possibility.

Damp walls & floors

Damp walls
damp wall paper
Patchy wall condensation is often confused with penetrating damp. Removal of a small area of plaster should tell you which it is. If it is condensation, the brick area behind will be perfectly dry; if it is damp, try to find the cause. At ground floor level it could be a faulty damp proof course; upstairs it may be a faulty gutter or down pipe or driving rain on porous solid brickwork might be the reason. Try to increase the circulation by warm, dry air in the affected area, but remedy the cause of the problem as soon as possible otherwise the trouble will recur.

Those with a high gloss finish are most susceptible to condensation.

Plasticine condensation test
To test for damp floor, place piece of glass on ring of Plasticine over affected area. Moisture on underside of glass indicates penetrating damp. Moisture forming on top of glass indicates condensation present

Damp floors
These are often caused by damp from the outside and not by condensation. You can make a simple test to see which condition is present with a piece of glass on a ring of Plasticine. Condensation on floors usually occurs with cold surfaced materials on concrete, such as tiles in the kitchen. The most effective remedy is to substitute existing flooring with warm-surfaced flooring.

Repairing plaster

Few homes escape damage to plaster caused by wear and tear, settlement of the main structure or through damp or excessive heat. Not only does it look unsightly, but it can become a major problem. So tackle the job early and save yourself time and trouble.

plastering company robuild london

The thought of having to repair damaged or flaking plaster may be fairly daunting to some people, but tackled in the right way with the right materials it is a relatively straightforward operation. Obviously it is quite a different matter if you have to replaster an entire wall or ceiling, in which case this is probably best left to the professional. But most of the small repairs normally required in the home are well within the capabilities of the DIY enthusiast.

Ceiling cracks
These are caused by the movement in roofing and flooring joists, leading to the plasterboard (where fitted) parting at the joints. Hairline cracks can easily be filled. With larger gaps you should seek professional advice.

Wall cracks
These are more likely to occur in new houses and are caused by the settlement of the main structure. The area most likely to be affected is the angle between the wall and the ceiling. Apart from filling in these cracks, which are likely to reopen later, one of the most effective methods is to cover over the gaps round the room. This can be done simply by fitting cove. Unsightly cracks across the wall may also be caused by settlement and normally only affect the plaster. If, however, you get a wide diagonal crack appearing not only in the plaster but also in the wall, this could be a major problem and professional advice should be sought immediately. When this happens it is usually on external walls and is clearly visible from the outside as well.

Filling cracks
Common hairline cracks can be repaired simply and quickly. Rake out the affected area with a sharp knife or the edge of a paint scraper. Cut a ‘V’ shape into the wall along the crack so that it is widest at the deepest point of the crack. This allows you to push the filler into the cavity dovetail fashion to prevent it falling out on drying. Apply cellulose filler with a flexible steel filling knife. Use either a 75 or 100mm filling knife, the larger size being preferred since you can work quickly over large areas. Don’t confuse this knife with a paint stripping knife, which looks similar, but must not be used as a substitute. The blade, which will bend about 90 degrees, should be perfectly straight and undamaged. Correctly used the knife can be used to give a smooth finish and make the job of rubbing down later unnecessary. Otherwise rub down with medium fine, then fine, glasspaper when the filler has completely dried, before redecorating.

Replacing loose plaster
Plaster often comes away from the surface around fireplaces. It can work loose due to vibration such as excessive hammering near the affected area – possibly when fitting a door or window frame. One simple test for loose plaster is to tap the suspect surface with the handle of a knife or a small blunt instrument. A hollow sound indicates poor adhesion between the plaster and substrate. Lift all the loose pieces with a broad knife and clean the surface beneath with a soft brush.

If you are dealing with only a small cavity you will probably get away with filling the area with fresh finishing plaster. In the case of a deep cavity. first apply a plaster undercoat. Wet the wall thoroughly, then roughly fill the cavity to within about 3mm of the original plaster surface, applying the undercoat with a plasterer’s trowel. The undercoat will dry with a rough texture which will provide a key for the finishing plaster. You will find a small ‘hawk’ useful to carry the plaster to the wall area after mixing it; make one by nailing a square of plywood to a short length of broom handle. When the undercoat is quite dry, mix up enough finishing plaster to a creamy consistency to complete the job. In powder form it does not keep that long and old plaster will often set too quickly to enable you to spread it properly; in this case the application will just crack and fall away.

If you find the plaster is hardening before you have a chance to use it, take it back to your supplier for replacement. To complete filling, go over the undercoat surface with a dampened brush, put a generous amount of plaster onto the bottom of a wood float or plasterer’s trowel and apply it into the remaining cavity. When the cavity is filled you can rule off the plaster. Using a timber straight-edge, which must be longer than the area being repaired, start from the bottom and work upwards over the new plaster with a sawing action, making sure both ends of the timber keep in contact with the surface of the existing plaster. This method ensures high spots are removed and low spots are built up as excess plaster is pushed up the wall, giving a level finish. When the plaster has almost set, rub a plasterer’s trowel over the new surface to give a smooth, polished finish. Lift the front edge of the trowel away from the wall so only the back edge is in contact; this will prevent the trowel cutting into the new plaster. Alternatively wait until the plaster has set completely and apply a layer of cellulose filler over the fresh plaster using a filling knife.

Repairing external corners
In any room it is the plaster on external corners that is the most vulnerable to damage. You can repair small holes and chips with cellulose filler as described earlier. When making good these small areas, apply the filler with a flexible filling knife working in each direction away from the corner. When dry the filler can be rubbed down lightly to form an edge to match the rest of that corner. With a badly damaged corner you will make the best repair by building up the corner with a plaster undercoat, then applying a layer of finishing plaster. Remove any loose plaster and clean back the area with a soft brush. Fix a batten, which must be longer than the affected area, to the wall so its edge is in line with the existing front wall plaster – and flush to the corner. Either hold the batten in position as you work or tack it lightly to the wall with masonry nails, knocking the points of the nails through the batten before fixing. You can screw it into position by drilling the necessary holes in the batten and the wall, plugging the wall and inserting screws through the batten.

Make sure you fix the batten well clear of the affected area or you may cause further damage. Build up the level by applying the undercoat plaster with a trowel or float, always working away from the corner. On one side, plaster the area to within about 3mm of the original surface, then move the batten to the other wall to complete the undercoating. When this is dry, complete the repair with finishing plaster, using the batten on each wall as before. If you nailed or screwed the batten to the wall, fill the holes with any plaster you have left over or with cellulose filler. Before the plaster sets hard, round off the corner by rubbing your fingers over the plaster to form an edge to match that on the rest of the corner. Use glasspaper if the plaster has set really hard.
plastering walls ceiling

Fixing curtain tracks

Fixing curtain tracks

Unless you are fitting the track in the recess above a window, or you want wall-to-wall curtains, the track should extend either side of the window so the open curtains will hang neatly to the side without cutting out any light. If, however, you have a wide window which you would like to look narrower, you can flt the track just to the end of the window so when the curtains are drawn back they cover the frame and part of the window itself. The easiest way to put up a track is to screw the fixing brackets to the top of the window frame. Fixing instructions are usually supplied with new track. Always fit the number of brackets recommended by the manufacturer for the length of track used and make sure there is a bracket close to each end to support the weight of the curtains when drawn back. For sill length curtains fit the brackets at equal heights from the sill (or from the floor for floor length curtains) to ensure the bottom hems of the curtains hang in line with the sill (or floor). Fix the end brackets at each side of the window, then stretch taught a length of string between them and use this to align the other brackets, spacing them at equal intervals.

window curtains bedroom

If you have to fix the brackets directly to the wall make the fixing holes with a masonry drill bit, which has a specially hardened tip for drilling walls. The masonry bit can be used with a hand wheel brace, but it is much easier to use an electric drill set at slow speed. You can make the holes with a cheap, easy-to use tool called a jumping bit, which you tap into the wall with a hammer and twist occasionally to clear the dust from the hole. Many houses have concrete lintels above the windows and you may find it difficult to make even with a hammer drill the going can be slow. To reduce the number of fixings in the lintel you can screw the appropriate length of 12mm thick timber above the window and fix the track brackets to this. Alternatively, fit a long curtain pole which will extend far enough on each side of the window to avoid the lintel. When you have made your holes in the wall above the window, it is vital the fixing is secure since the weight of the curtains will otherwise quickly loosen it. Having inserted suitable wall plugs, secure the brackets to the wall with screws.

Curtain tracks

window curtain bedroom

The extensive range of curtain tracks enables you to choose the type which best suits your room and the curtains you wish to hang. Make sure the track is strong enough to take the weight of the curtains; some plastic track will not be sufficiently sturdy to hold full length curtains, which may have to be hung on metal track. If the track will be visible when the curtains are hung, choose either a decorative track which blends with the room, or a plain. unobtrusive one which you can paint or leave white. Alternatively hide the rail by fitting a pelmet or valance in front of it.

Pelmet tracks
The traditional and still popular I-section track is not very attractive and therefore is mostly used with a pelmet or valance. It can be made from brass, aluminium, plastic or plastic-covered steel. Brackets. which clip into the top section of the track. hold the rail to the wall, window frame or ceiling. The curtain hooks are attached to double-wheel runners (on metal rails) or to nylon gliders (on plastic tracks). Strong enough to support heavy curtains. I-section rail is sufficiently flexible to be bent into tight curves (useful for fitting square bay windows or for forming overlaps). You can buy ready-made wood pelmets (finished in dark walnut, other timber or gilt) with the curtain track ready fitted and corded on a track board; this is attached by metal clips to the front and side assembly.

Non-pelmet tracks
Most modern tracks are designed for use without pelmets or valances. Some of these have the runners concealed in a box section or clipped over a flat rail. Box rails are normally flexible enough to be used in bay windows and recesses and can be bent to a radius as small as 50mm. But if you have to bend the track as tight as this, check with your supplier that the track is suitable. Tracks for use without pelmets are normally made from plastic or aluminium. Apart from a plain track, various finishes are available such as silver or gold coating, wood grain and carved wood. And you can buy ornamental finials (end pieces) which clip onto the track. You can also buy a fluted trim to clip over straight lengths of track to give the impression of a cornice pole. Another type of non-pelmet track is the neat, inconspicuous U-shaped channel, in which gliders slide. Ideal in recessed windows, it blends well with the clean lines of modern decor. Made from plastic or coated aluminium, it can be mounted on the wall or ceiling but is only suitable for straight runs. It is often used with a second track for hanging nets behind heavier curtains.

Cording sets
Available as optional extras with many tracks, these prevent wear and tear on the curtains caused by hand-pulling; even long curtains can be drawn with ease. Many cording sets have a device included in the kit to assist in the overlapping of curtains. You can fit any good corded curtain track with an electric curtain motor and connect it via a conveniently placed two-way control switch to a socket outlet or fused connection unit.

Curtain poles
For straight runs only, the old style curtain or cornice poles are again popular. The simplest design is a stout pole (of wood, plastic or metal with a brass finish) with plain or ornate turned ends mounted on matching brackets. Many modern curtain poles are made in the same styles as the old brass ones, but with easy-running false rings which slide in channels hidden behind the poles. Some poles are telescopic, fitting a range of widths, and they are often supplied with integral cording sets.

Hanging nets
Net or cafe-style half-pane curtains are usually hung on plastic-covered wires pushed through the top hem of the curtains. You can adjust the gathers as required, but it is almost impossible to open the curtains completely; so this method of hanging is really only suitable for curtains which will be left undisturbed. The neat and simple way of fixing plastic-covered curtain wire is by using rings and hooks. The ring screws into the end of the wire and the hook is screwed into the window frame. This can be done by hand, but if the wood is too hard or you want to put the fixing into the wall (if the window frames are metal) you can use a small round head screw instead.

With wall fixing you will have to drill a hole and plug it before inserting the screw. Make sure you leave a 6mm clearance between the screw head and the wall to allow for the ring to be hooked over the screw. Trim the curtain wire with pliers so it is slightly shorter than the width required. This ensures the wire is really tight when hung and the curtain does not sag. Screw the rings into each end of the wire, thread the wire through the top hem of the curtain and stretch the wire across the window, hanging it over the hooks or screws already fixed at each end. The curtain wire does tend to sag, so hang only lightweight curtains. (If you are hanging floor-to ceiling nets, use the neat U-channel track.)

An alternative method of hanging fixed net curtains is to use lightweight curtain rods (wood dowels are ideal) although you will not be able to open the curtains completely. The rods are fixed near the top of the window frame using curtain rod brackets; the cranked version is screwed to the window frame and the straight version is fixed to each side of the window recess (useful for metal window frames).

Repairing Concrete floors

concrete screed floor

Greasy or oily patches on a solid floor in a garage, shed, cellar or kitchen, must be removed before you lay floor coverings. Grease can build up to such a level that it becomes a hazardard, you should apply a concrete paint or a proprietary grease removing solution, which you can buy from motor accessory shops. Scrape the floor to remove as much grease and dirt as possible and brush on grease remover solution until the surface appears thoroughly wet. Leave for up to 15 minutes for the grease to soften and agitate it with a stiff brush from time to time. If necessary, apply more solution until the grease stain takes on a soap-like appearance. Wash with water and brush the floor; repeat the treatment if the stain remains after the floor has dried out.

Dusty concrete
This can be cured with a concrete hardening and dustproofing liquid. Sweep the floor or vacuum it clean if possible – and apply the liquid with a brush, according to manufacturer’s instructions (two coats may be required). You can use a PVA bonding agent diluted with water, but allow the treatment to dry before subjecting it to normal traffic. According to the wear the floor receives, the treatment may have to be repeated every one or two years. If you need a more durable coloured finish for a garage, store or outside WC, you can apply a brush-on floor sealing compound to give a tough, dustproof coating which is impervious to water and oil.

Fixing mirrors

Mirrors play an important part in interior decoration; if they are carefully placed, a small room can be made to look larger and a dark room appear lighter. In every home there is a place where a mirror can be used to great effect in an alcove, behind display shelving. in a recess or covering a door. But remember a mirrored surface will reflect everything which stands in front of it; so avoid overdoing it by placing mirrors on an adjacent or facing wall since the effect might be confusing and not what you expected.

mirror bathroom ensuite

A wide range of mirrors is available, either drilled for screw fixing or undrilled for other methods of fixing. Your glass merchant will be able to supply you with a mirror of almost any shape or size. Any top quality glass, free of imperfections, is suitable for silvering; 6mm float glass is used for most of the larger mirrors. It might be necessary to use a thicker glass for mirror table tops, depending on the size requirements; your glass merchant should be able to advise you. Decide when placing a special order for a mirror whether you will require a screw fixing. If you do. it is worthwhile getting the supplier to do the drilling for you. Large mirrors are expensive and, since the additional charge for drilling is very reasonable considering the overall cost of the mirror, it is best not to risk drilling the holes yourself. All mirrors should have polished edges, unless they are to be set into a hear,y rebated frame, when a clean cut edge will do. Take care when handling cut mirrors with unpolished edges; wear leather gloves since the edges of the glass are razor sharp.

Screw fixing
A drilled mirror can easily be fixed in place, unless the wall surface is uneven; a really badly undulating surface should be covered with a base board of plywood or chipboard, although it is seldom necessary to go to this trouble. First support the base of the mirror flat against the wall in its final fixing position. It is wise to get help at this stage, if only to check the mirror is set at a true vertical on the wall. Once you have established the right position, mark with a pencil through the drilled holes onto the wall behind. Remove the mirror and drill the wall at these points, using the correct size masonry bit and wall plugs for the mirror screws. The screws used have rubber or soft plastic spacers and collars. Various types are available, although the principle is the same with each. The screw passes through a sleeve, which is centred in the hole of the mirror. At the back a spacer washer fits between the mirror and the wall, while a cup washer is placed between the face of the mirror and the countersunk head of the mirror screw. Great care must be taken when tightening the screws; work round them in turn, gradually tightening each one until is head gently squeezes the soft cup washer on the face of the mirror. Check at this stage the mirror is firmly held against the wall. If it is not, don’t tighten the screws further since this will cause the mirror to break. Remove whichever screw is not gripping the mirror firmly, insert packing behind the spacer washer to fill the remaining gap and screw through the packing into the wall. The decorative heads of the screws can then be fitted into the fixing screws to conceal the screw heads and the washers beneath.

Mirror clip fixing
Undrilled mirrors can be mounted on a wall using mirror clips. Several types are available, including corner clips, plastic spring clips and hook-on clips. With the hook-on type the bottom clips are screwed to the wall in accurate alignment, so the bottom of the mirror rests on the upward facing jaws. Check your levels carefully before finally fixing these clips. The upper clips have a long slot in the back plate through which they are screwed to the wall, tightly enough to allow the clip to slide up and down behind the screw head. The mirror is then placed in the bottom clips and pushed flat against the wall, while the downward facing jaws of the upper clips remain in the open position. The upper clips are then slid down so the jaws hold the top edge of the mirror. The mirror can be easily taken down by opening the upper clips and lifting the mirror out of the bottom ones.

Frame fixing
Small mirrors can be framed and backed and hung in position using mirror plates or chains. Larger mirrors can be built into wall fitments and held with facing mouldings and beading. A mirror can also be placed in a sliding frame to provide a mirrored door for a unit.

Screws, nuts and bolts

Screws and bolts provide enormous holding power, but are simple to fix. The types shown here are the ones you are likely to come across when fixing both wood and metal, together with the most commonly used accessories.

Screws – common types

1. Countersunk wood screw.
For general use; head let in flush with wood surface.

2. Pozidriv head countersunk screw. Fixed with special non-slip screwdriver.

3. Raised head countersunk screw. For fixing door-handle plates, etc, to wood; decorative head designed to be seen.

4. Round head screw. For fixing hardware without countersunk holes to wood.

Screws – special use

5. Coach screw.
Extralarge wood screw with square head; tightened with spanner.

6. Self-tapping screw. For sheet metal; cuts its own thread as it is screwed in; has slot, Phillips (cross), or Pozidrive head.

7. Dowel screw.
For invisible fixings; two pieces of wood twisted together to tighten.

8. Handrail screw.
For ‘pocket’ screwing; head screwed on from side with screwdriver.

9. Cup hook and screw eye.
Large number of shapes and sizes available.

Screws – accessories

10. Flat washer.
For round head screws; spreads load to give a strong grip.

11. Screw cup-raised type.
For countersunk or raised head countersunk screws; spreads load, improves appearance.

12. Screw cup-socket type.
For countersunk screws; hammered into pre-drilled hole for a completely flush fixing.


13. Machine screw.
Not a screw, but a bolt. Small sizes only; available round, pan, cheese or countersunk heads.

14. Machine bolt.
Large sizes only; available with hexagonal or square heads.

15. Coach bolt.
Large bolt with a ‘square collar under the head that stops it from turning when the nut is done up.

16. Rag bolt.
For bolting wood or metal to concrete; jagged head is set in wet concrete and holds bolt firmly when concrete dries.


17. Hexagonal nut.
Commonest type, available in a wide range of sizes.

18. Square nut.
This type available in large sizes only, e.g. for coach bolts.

19. Flat square nut.
Small sizes only; thinner than l8 in proportion to width.

20. Handrail nut.
Used on handrail screw (8) and in other places where nuts have to be tightened from the side in a small space.

21. Wing nut.
Tightened by hand;’for use where nuts must be undone quickly.

22. Domed nut.
Decorative nut, generally chromium plated.

23. Locking nut.
For places where vibration might make nuts undo; has fibre ring inside to make it hard to turn.

Bolts accessories

24. Flat washer.
Same as (10); used in same way; also makes nuts easier to turn.

25. Single coil washer.
For metal fastening only; spring shape prevents bolts from undoing.

26. Internal and external tooth washers. Gripping teeth keep bolts from undoing.

27. Timber connector. Used between pieces of wood bolted together.