floor joist repair

floor_joist_repairFortunately, joists do not develop as many faults as floorboards, but defects can occur, especially if unseasoned wood was used in the first place. A joist can twist out of true. A symptom of this would be that a floorboard would be seen to be twisted, but could not be nailed down flat. Or a joist can be attacked by woodworm or dry rot. The floor will seem weak or unstable if this is the case. If you suspect a weak floor you should always lift a board or two to discover what is wrong, it must be stressed that floor joist repair is a major undertaking,  and not to be embarked upon lightly. They involve a great upheaval, especially on upper floors, for your work will almost certainly damage the ceiling below. Since each joist carries every board in the room, a large part of the floor, if not the whole lot will have to be taken up, which will mean the room will be unusable, as will any room below if you interfere with its ceiling.

A joist might be damaged along part of its length — a tendency for the floor to sag or feel unstable at one point is an indication of this, in such a floor joist repair case, saw out the damaged section as detailed below, buy a new length of timber of the same size, and bolt it to the cut ends of the old joist. If a joist is twisted or bowed it is often possible to straighten it by fitting struts between it and the joist on each side. Should all the joists be twisted, struts of fairly strong timber, 25 mm thick, and almost as wide as the joists are deep, will have to be fitted between each of them. They are cut to a length equaling exactly the spacing between the joists, and are fixed by skew—nailing. If this remedy does not work, the joists will have to be replaced.

chipboard flooring sheets

In many modern buildings chipboard flooring sheets is used on top of the joist instead of floorboards, because it can be up to 30 percent cheaper. It must, however, be a special type of chipboard suitable for the job. Chipboard is a good base for all types of floor covering and can be an attractive surface in its own right when sealed. Quality chipboard flooring sheets can be bought in three different edge profiles, square-edged, tongued and grooved on two sides or four, or loose-tongued. Chipboard has one other big advantage over floorboards, apart from cost: it is a more stable material than natural timber, and therefore less likely to twist, shrink or warp. It is not, of course, as strong, but is perfectly adequate for the job.

lf any of the panels that make up a chipboard floor become damaged, replace them. Should the panel be a large one, you might be able to minimize costs by replacing just half of it. First ascertain by probing as before, whether a `T and G’ board has been used. If it has, the tongues on all sides will have to be removed, in the same way as for floorboards. Prise up the board, using a large, old screwdriver or chisel. Begin along one edge. Once you work this free, the rest will come up easily. When the board is raised, measure its thickness, and buy a replacement of the same dimension. In the meantime, leave the damaged board loosely in place so that no one will fall down the hole. No matter what type of edge profile was used previously, the replacement will have to be square-edged. Chipboard can also be used to replace a damaged plank floor.

chipboard flooring - chipboard sheets

As already mentioned, chipboard flooring sheets come in two thicknesses – 18mm and 22mm. For the former the joists must be no more than 18 inches apart, while for the latter they can be up to 24 inches. Local building regulations may specify minimal. Square-edged boards should be supported on every edge. Their long edges go parallel to and should fall in the middle of- the joists. This means that, if you cannot buy a standard sheet size to match your joist spacing, you will have to cut the chipboard flooring sheet to width. The ends of the sheets are fixed to short lengths of timber, skew-nailed to the side of the joists. These lengths of timber are known as noggins and they should be 38 mm wide. The boards should be nailed in place, the nails being about 9mm from the edge of the board, and 8 to 12 inches apart round the perimeter, 16 to 20 inches on intermediate joists. Tongued-and grooved boards go with their long edges across the joists. They must, however, be supported at the ends, so cut them to a length that ensures their short edges fall in the middle of joists, one 25mm from each edge, the others spaced between. Study the foregoing information, look at the joist spacing in your home, get from your supplier a list of the sizes of board he can offer you, then work out which it would be best for you to buy.

The temptation will be to get the biggest boards possible because that would speed up the work. However, do re- member that chipboard is such a heavy material that some of the larger sheets are unwieldy, so unless you can be sure of help, you might get along better with a smaller size. When your chipboard arrives, it must be properly stored until you are ready to use it, bad storage can cause permanent distortion of the boards. Stack them flat, indoors. It is a good idea too, to loose1ay them in the room where they will be fixed for at least 24 hours in order to condition them to the moisture content of the room. The edges of all types of chipboard flooring sheets should be tightly butted up against each other, and you will get a stronger result if you smear a pvc woodworking adhesive on the meeting surface. But where the boards meet the walls of the room you should leave an expansion gap. This gap should be 2 mm for every meter (40 inches) of floor, with 10 mm as the minimum.

Just as when you are laying hardboard, you should break the bond so that the cross joins are staggered, and you achieve this in just the same way: when you saw a board to length to complete the end of the row, use the waste to start off the next row. Should there be electrical or plumbing connections under a chipboard floor it is a good idea to form a trap above them. Make sure it is supported by joists or noggins on all edges, and fix it with screws rather than with nails so that it can be raised easily. Chipboard flooring is easy to make, by just normally using chipboard flooring sheets or tile. Besides, you can bond all types of flooring, both sheet and tile, directly to chipboard. If you will be using an adhesive with a high water content, seal the floor first with a polyurethane lacquer.