Joints in flooring, to link coverings and minimise movement, are often overlooked by specifiers. Barbour Index and Scott Brownrigg explain why this isn't a terribly good idea

QJoints in flooring are particularly important to the specifier because flooring is subject to such heavy wear and tear. As well as being necessary where there is a limit to the area that floor coverings can span, joints help to accommodate movement and provide important junctions at walls and thresholds. Despite this, they are frequently overlooked and responsibility for them is often passed to the supplier or installer. The specifier should look closely at joints and identify the exact position and layout for a successful installation. They should also include the type of material and fixing for the joints in the specification and discuss this with the manufacturer and installer.

Consider the flooring product and what sizes it is available in. Is it supplied as a large sheet on a roll or as tiles? Then examine the preferred joint positions. These will be determined by factors including aesthetics, practical considerations such as the need to repeat substrate construction joints in the finish and the desire to minimise waste. For example, specifying the design layout of joints is important, as a joint in the middle of a floor or in another inappropriate position will look terrible, particularly in a small space. Minimising waste is of course vital from the sustainability perspective as well as cost and will require early and consistent selection of all materials.

1. Threshold joints

Joints at thresholds and transition spaces need careful consideration. The most important is the entrance threshold as weather resilience, smooth transition between the two areas and slip resistance must all be addressed. Many products provide a good deal of weather protection but be sure to think about the levels of exposure and traffic and the door detailing. Of course, it's also vital to ensure that the flooring material is appropriate for the location and that any trims are securely fixed.

Also be careful that the threshold joint itself doesn't become a trip hazard, as a change in level of just 10 mm can be a problem if the change in level is sudden. Where changes in level are necessary, ensure they are gradual. Also watch out for the potential slip hazard presented by some metal threshold solutions as a smooth surface can be surprisingly dangerous. Specify a textured upper surface.

2. Other joints

Away from the entrance the same principles still apply, although problems presented by entrained dirt and moisture are likely to be less serious. Nevertheless joints must be capable of being easily cleaned and if the joint is raised or recessed its edges need to be smooth and well sealed.

Also bear in mind that, in large installations, the jointing material itself may have joints that need to be considered and defined. Curves may also be difficult to specify with most jointing systems. Plastic or built-up products should then be considered. Some systems may result in small faceting of the joint that may detract from the effect required.

3. Tiles

Tiles can be problematic because they need expansion joints, and joints are intrinsic in tiled floors anyway. Tile joints should be proportionate to the tile size, type and application. Some high quality tiles can be jointed finely but generally the rougher the surface texture the wider the joint.

On average ceramic or stone tile joints will be between five and 10 mm. These should be set just below the tile edge, which may in turn be set below the general finish. The joints should be smooth and linear. Colour choice is also important as this can have an effect on the overall colour of the floor. Additionally, light coloured joints are very difficult to keep clean, particularly in heavily used areas. It is better to specify a jointing material that is a similar or darker colour to the tiles from the outset as light colours will darken over time.

Ensure that a movement joint is included between the floor and any skirting tiles. A dedicated, fully glazed transition tile, curving between the floor and the wall, with a radius of 20 mm or greater, will greatly ease cleaning and help maintain a good appearance for many years.

4. Carpet

Carpets come in broadloom or tile formats.

Most broadloom carpets are available in varying sizes.

They can be stitched together or jointed by using tape on the back and may also be glued down. Although these joints may not be obvious, do ensure that they are positioned to avoid heavy wear areas. It may be advantageous to position joints so that any pattern helps disguise joints. Plan the carpet layout at an early stage to minimise waste.

Connection strips that join the carpet to other carpets and materials come in a range of materials and finishes including brass, stainless steel and plastic. Bear in mind that the ends of these profiles will abut a different material, such as a door frame.

Tiles are available in a range of sizes and are designed to butt joint on a suitably prepared subfloor. Ensure that the fixing medium that is recommended for the floor tile is actually used. Tile creep can be a significant problem and can result in unsightly gaps.

It is difficult to remedy this without completely relaying the whole area.

5. Timber

Joints in timber floors are particularly important because in addition to most of the constraints already mentioned above, the natural movement of the timber has to be accommodated. All types of manufactured wooden flooring have jointing systems that allow for this movement. An allowance must be made at the perimeter of the floor to take up this movement. In extreme circumstances, particularly where excessive moisture is present, the floor can expand to the point where it pinches together and heaves upwards. Check that the manufacturer's detail can accommodate normal degrees of movement.