Laying quarry tiles

Quarry tiles—unglazed, baked, vitrified clay tiles—were once the standard hardwearing floorcovering in the UK for kitchens, hallways and factory floors. Though they have since been superceded by modern vinyl coverings, they are now coming back into fashion because of their rustic, natural appearance and hardwearing properties.

Modem quarry tiles come in all shapes and sizes, and in a variety of colours. Natural reds, buffs, browns and blue-greys are all available, together with pigmented tiles which each contain several hues. Texture varies too, from perfectly smooth to rough and irregular, though most fall somewhere between the two.

The chief advantages of quarry tiles are that they are hardwearing and easy to keep clean—making them ideal for kitchens, laundries and utility rooms. The drawbacks are that they are hard —meaning that anything which falls on them is liable to break—and cold, though the latter is unlikely to present problems in a centrally-heated home or a warm climate. Laid properly, a quarry-tiled floor is practical, easy on the eye, and will last a lifetime.

Size and type

The most common sizes of quarry tiles are 152mm X 152mm, 203mm X 102mm and 228mm X 228mm, though smaller and irregularly shaped tiles are also available. Thicknesses range from 8mm to 25mm and in the case of the more expensive hand-made tiles, vary slightly within a batch. In fact, the true size of hand-made tiles can also vary, making regular jointing impossible. Machine-made tiles often have spacer lugs to help keep the joints between them to an even thickness.

Many quarry tile ranges include special border tiles for edging work. Bull-nosed tiles are used where the edge meets another covering—such as a carpet—or ends at a step. Coving tiles are used against skirtings to make a clean join and to prevent water from splashing the woodwork when you clean the floor.

Suitable surfaces

Because quarry tiles are heavy and brittle, it is important that they go on a solid, level surface. Though a concrete floor obviously provides the most suitable base, the tiles can be laid^on a wooden floor providing this is covered first with sheets of plywood or flooring grade chipboard.

Make sure that the sheets are flat before you lay them. Pin them to the floorboards at 100mm centres to prevent twisting or warping later.

Quarry tiles can be fixed in one of two ways: with a heavy-duty ceramic tile adhesive—such as Ardurite—or in a bed of sand and cement mortar. The first method is much the easier but is suitable only for surfaces which are dead level—such as a recently laid screed. Neither is it suitable for laying hand-made tiles with variations in thickness, because the adhesive cannot take up the different levels.

Using a mortar bed is the more traditional way of fixing quarry tiles and is particularly well suited to rough, dusty concrete floors where it enables you to level and cover the floor at the same time.

Using adhesive

The procedure for laying tiles with adhesive follows closely that for vinyl and cork tiles. Having chalked a cross in the centre of the room, based on the main doorway or entrance, plan a dry run of tiles and make small adjustments to minimize the amount of cutting to be done at the edges.

Make sure that the adhesive you use is suitable for the base surface. Flexible surfaces such as plywood and chipboard require a special, flexible adhesive which your stockist will supply.

Spread out the tile adhesive with a notched trowel, to an area of about lm2 around the centre of the cross, then start laying the tiles.

If the tiles have no spacer lugs, mark off six tile widths with 3-4mm spacings for the joints on a length of planed batten and use this as a guide.

After you have laid the first lm2 of tiles, spread down more adhesive and continue laying in this way until you are left only with the edges to fill. At this stage you will probably have to cut the tiles to fit.

After the tiles have been laid and allowed to set, fill in the joints between them with a proprietary grouting compound suitable for flooring use. Rub the joints flush with the surface of the tiles, rather than run through them with a stick.

Alternatively, should you prefer to give the joints a coloured finish, use a mixture of fine white sand, cement and colouring additive.

Laying tiles in a screed

For quarry tiles to rest on a thin screed of mortar, they must be laid in sections or ‘bays’ across the room working back towards the main doorway or entrance. Each bay must be screeded, levelled, tiled and then levelled again before you start work on the next.

Though several forms of screed can be used to bed the tiles, the most commonly used is the semi-dry screed. In this, the mortar—three parts sharp, washed sand to one of Portland cement —is mixed with only enough water to bind the ingredients together. That is, it should be damp and crumbly.

A semi dry mix takes longer to go ‘off’ than other types, allowing you plenty of time to level it, lay the tiles and adjust them. Yet if properly compressed, it holds its shape well enough to allow you to walk lightly over the tiles on the same day that you lay them. Drying time for the screed with the tiles on top is normally 24 to 36 hours.

Setting out the first bay

The first bay should run across the room, as near to the far wall as you can get it. Any awkward areas created by obstructions such as kitchen units can be bypassed and then filled back from the bay.

To mark the edges of the bay, you need two 50mm wide battens long enough to stretch across the room-Their thickness should be equal to that of the mortar screed—normally 12mm at the highest part of the floor.

Before you place the first batten, run over the floor with a spirit level to check that it is not substantially higher near the main entrance than at the first bay. If it is, make allowance for this when you bed the batten in position. Make sure that all subsequent battens are level with the high point.

The batten must rest on a thin bed of the screed mortar. Lay this out roughly then press the batten on top and weight it with your straightedge. With the spirit level also laid on top, check the batten for level. Make small adjustments by tapping it down or packing more mortar underneath as necessary.

The second batten—marking the edge of the bay—is bedded in exactly the same way. You then stretch the spirit level between the two battens and adjust them until they are level with each other. Do this on both sides of the room. Position the second batten so that the bay is large enough to give a good tiling area but narrow enough to allow you to stretch to the far side without risk of falling off-balance.

Screeding the first bay

Shovel the semi-dry mix into the bay and spread it out roughly level with the battens using a float. Fill any indentations which appear on the,

Cutting quarry tiles

Quarry tiles, because of their thickness and strength, are generally very difficult to cut. Though the thinner ones —below 6mm—can sometimes be cut in the same way as ordinary ceramic tiles, the thicker types demand more substantial methods.

For these, you need a tile cutter— normally available for hire from tile stockists—a pair of tile nippers or pincers, and a pin hammer. Even with these, you cannot expect to make really intricate cuts and still keep the tile in one piece. Where such cuts are called for, use two or three pieces of tile instead of trying to cut one to fit.

To make a straight cut through a tile, first measure it against the gap and mark it. Set the tile in the cutter so that the groove aligns with the marks. Then pull the sliding lever upwards and across the tile to score a cutting line.

Afterwards, set the lever about 10mm in from the edge of the tile and press down hard. If you cannot get the tile to split after repeated attempts, remove it from the cutter, hold it and tap the back sharply with the pin hammer. To trim off a thin piece of tile, hold I it with the back side up against your le.g. and gently hack away small pieces of material using the hammer. When you have chipped out about half the thickness, turn the tile over and remove the remainder.

If you have to make cuts into a tile, never try to remove too much in one go. Start off the cut with the hammer, working alternately from both sides and finish off with the pincers. surface and make sure that the mix is well compressed.

Keep adding and compressing mortar until the whole bay is covered and the mix is slightly proud of the battens. Then draw your straightedge along the battens so that the mortar is scraped off level with them.

Afterwards, flick away any loose mortar around the edges, lightly compress the scraped surface with the float, then check it all over with the spirit level. Correct any humps or depressions in the mortar and, if necessary, run over it again with the straightedge. When you have got the bay dead level, fill in and level any awkward areas behind it in exactly the same way.

Finally, dig out the embedded first batten. Fill the narrow gap left behind with mortar and level this off with the surrounding surface.

Planning

When you are laying quarry tiles on a screed, it is not possible—or necessary —to lay from chalked lines in the centre of the room so that the lines of joints end up ‘square’. Instead, you must lay a dry run of tiles square to the main entrance of the room, back towards the far side where you will begin tiling.

Run the tiles up over the wet screed in the first bay, adjust the run so that you are left with equal tile cuts of half a tile or more at both ends, then mark a line to indicate where the last full tile ends. You can do this by scoring guidelines in the screed with a trowel and a straightedge.

Afterwards, lay a second dry run parallel to the line across the bay. Again, adjust the run so that the tiles to be cut along the walls are a half tile size or more. And as before, mark the position of the first full tile.

When you are laying the dry runs, be sure to allow for the width of the joints. For thin, machine-made tiles these can be as little as 4mm; for handmade tiles leave between 6mm and 8mm to allow for the slight variations in size between tiles.

Tiling must begin from the lines you have marked: towards the main entrance as you tile the first bay and back towards the far wall as you fill in any awkward areas. Remember that no matter how many times you alter the positions of the lines, you will never be able to eliminate intricate the differences in tile sizes while still maintaining a good overall effect.

When the tiles are in their final positions, beat them down hard with a sturdy piece of timber to remove any high spots and pack them into the bedding. At the same time, make constant checks for level with the spirit level.

Finally, to provide a good base for grouting later, make up a very dry mix of the mortar. Brush this over the surface of the tiles so that it fills all the joints to an even depth , then sweep away the excess.

Subsequent bays

With the first bay completed, continue by screeding and tiling a second. Use the second batten from the first bay to form the first batten of the second and cuts completely: simply do your best to ensure that these are confined to unobtrusive areas.

Laying the tiles

As quarry tiles do not adhere readily to a semi-dry mix, the surface must be covered with a thin bonding layer after you have scored your planning lines.

Make the bonding from a mix of one part cement to one part water, further diluted until it forms a very thin paste. Pour it over the surface of the screed and level it out with a trowel or float until it just covers the mortar.

Position the first two or three tiles on the screed, in line with your planning lines, then tap them down firmly with a trowel handle. If necessary check them for level with the spirit level and measure the width of the intervening joints.

After this, simply continue filling the bay with whole tiles. Where necessary, work back from the planning lines to fill awkward areas behind the bay. When you have laid all the whole tiles, fill in the cut tiles at the borders. Each cut tile must be marked and cut individually to fit as quite large variations in size are bound to occur.

When the bay is completely tiled, you can begin evening up the joints. As the tiles are unlikely to all be the same size, this job is best done by eye. Make adjustments by tapping the sides of the tiles this way and that with the blade of your trowel. When you are happy that each is in the right place, tap it down firmly with the trowel handle. By levelling up the joints on every third row only, you enable the joints in between to take up so on. Be sure to check every new batten for level against the previous one or the screed will become uneven. On all but the largest floors, further dry runs and planning lines are unlikely to be necessary—as you tile, simply keep to the line of tiles and joints set by the first bay.

Grouting

When the entire floor is tiled and beaten, and the joints filled, you are ready to grout. Normally, a grouting compound of one part cement to one of water—mixed into a thicker paste than that used for the bonding coat—is perfectly acceptable. But if you prefer, you can use a mix of one part cement to one of fine white sand with colourant added to match or contrast with the colour of the tiles.

Using a semi-dry screed, you should be able to walk on the tiles at this stage without them becoming displaced. However, be sure to wear soft shoes and avoid ‘treading on the edges. To spread the weight of your body when grouting, kneel on a piece of 500mm X 500mm plywood or chipboard or balance on a wooden beam.

Spread the grout over the surface of the tiles with a squeegee, working over an area of about 2m2 at a time. Force the compound well into the joints so that it fills them completely and do not be deterred if the tiles get in a mess— they are easily cleaned.

After the squeegee, wash away the excess grout with water and a sponge. As you do so, make sure that each joint is rubbed smooth and that there are no gaps left unfilled.

Changing levels

An important point to bear in mind when quarry tiling is the change in level brought about by the screed, tiles and possibly also a plywood base. Though doors are easily altered to fit, the step caused by different floor levels presents more of a problem: it is a hazard and as such, may not satisfy building regulations.

Where carpet meets tile, the usual answer is to continue the screed under the carpet so that it slopes down gently to the original floor level over a distance of about 500mm. Set the slope roughly by eye then use the straightedge and spirit level to smooth it to an even finish.

An alternative solution, particularly suited to where the tiles meet another solid floor at a different level, is a wooden ramp. This can be sawn and planed to shape, drilled and plugged into the floor and then polished or coated with varnish.

Finishing

After grouting, the tiles will be badly discoloured with cement and grout. By far the best way of removing this is to rub over them with dampened sawdust once they have dried.

Rub the sawdust thoroughly over each tile with a circular motion then brush it away. If there is still some discolouration, apply a second batch and repeat the process.

When the tiles are clean, you can bring up their shine and natural colour with polish. Use a proprietary wax tile polish on the smooth, even-coloured type of tile; on the textured, mottled variety such as those shown use a thin application of linseed oil.

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