Flagstone Floors

IF YOU PLAN to build or have already built a room on a concrete Slab, you have the required solid footing for a flagstone floor Most people consider "flags," especially the bulk type that you cut and shape to fit, an outdoor material. While it's true that they fit nicely into most landscaping schemes, they can also be a "glamor'` material for indoor use—a relatively economical and most durable flooring that will give a room a distinctive decorator touch.

Flags indoors are economical, easy to put down, and add both beauty and distinction

A properly placed flagstone floor provides lifetime durability and ease of maintenance. The cost com­pares favorably or is even less than that for many other deluxe materials if you do the whole job.

Flagstone is purchased by the pound. It is cheapest when you buy it "as it comes"; that is, in various shades, sizes and thicknesses. Sizes shouldn't worry you too much since you'll have to cut and fit anyway. As far as color shades are concerned, contrasting tints are desirable to provide interest and add to appearance. Another thought here is that the difference in color is never too great, and the application of sealer and finisher after the floor is complete does much to even out the over-all tone.

The thickness of the pieces is a factor you should give much thought to. Since the thick pieces are heavier than thinner ones (that figures!) you'll get fewer of them per 100 lbs. and thus— and this is what counts—less coverage. If a piece of 1/2 in. flagstone weighs as much as a piece of 1 in. flagstone, it will cover, theo­retically, twice as many square feet. We say theoretically, because the cutting and fitting will reduce the coverage somewhat.

The thickness is also important when it comes to working with the stone. A more uniform thickness lets you use a more uniform mortar bed. You won't be able to buy flagstone so that all pieces are exactly the same thickness, but you will be able to buy so that all pieces fall within a certain range. This will cost you more per pound because the pieces have to be sorted by yardmen and you pay for the labor. You may actually save money, however. The extra amount you pay for select stone pro­vides you with more floor coverage be­cause the stones are thinner and you get more square-footage per pound. It will work out to your advantage both in money and labor if you can buy stone within a range of 3/8- to 3/4-in. thickness.

Indoors, or outdoors as below, flags require a firm, solid base, preferably concrete. Actually, this is a type of slate placed in random pattern.

Bulk flagstone is delivered in sheets that vary in size and thickness. By buying selected stone, you get pieces within a given thickness range.

Wide chisel and hammer are all you need for cutting. Be sure stone is on Hat. hard surface and that you cut by scoring continuous­ly on same, marked line.

You can also cut by "nib­bling." This is technique to use when fitting stone around an obstruction. It is just a question of chip­ping pieces with hammer.

When you buy, tell the man how many square feet you must cover; not how many pounds you want. He will have a pounds-per-square-foot figure for the stone you select. Add at least 10 per cent for waste and discards. The kind of pattern you de­cide on will affect the amount of stone you need. If you want a formal appearance with straight-edge pieces and uniform, small joints, you'll need more stone be­cause there will be more waste with ex­tensive cutting and fitting. If you're amen­able to a more rustic treatment—joints that are not uniform, smaller pieces to fill in spaces between larger stones, an irregular pattern—you'll save time and money because there will be less waste and the job will be easier.

Check frequently with 2x4 and level, both from stone to stone and across open areas as here. It's easy to go wrong if you don't keep checking.

Use the level alone to check between adjacent stones and as you place each piece. Be especially careful that all edges of stone are down flush.

Twist the new stone into place and use rubber mal­let for final touches. It doesn't take much to settle stone into the fresh mortar, so go easy on the banging.

Laying the Floor

The first step in laying a floor is to check the base to see if it's level. Chances are it won't be (the concrete slab that is, is a rarity). Once you convince yourself that the floor is not level (it may even have a dip or a dent or two), you must find the high spots. One way to do this is to cut up small blocks of wood that vary in thick­ness—1/8in. hardboard, 1/4 in. plywood, 3/8 in. plywood, 1/2 in. plywood and so on. Also have on hand a straight, 6-ft. length of 2x4. If necessary, run the 2x4 over a jointer to be sure it has one good, smooth edge. Choose arbitrary positions for two 1/2-in. blocks of wood and span them with the 2x4. Set a level on top of the 2x4 and replace one or the other of the two blocks with thinner or thicker pieces until the level bubble stays in the center of the glass tube. Now work from either one of the blocks in a different direction and follow the same procedure. When you've done this so your blocks are spread over the entire floor and the span from block to block reads level, you'll have a good idea what the surface of the slab is like. The areas with the thinnest blocks of wood are the high points, and from one of these—using a minimum mortar bed (1/2 in.) and the thinnest stone (3/8 in.)—you can start the floor. Chances are, the highest point of the floor will be in a corner or along a wall that rests on a deep concrete footing.

Minimum cutting and waste result if you use random pattern and joints that are not perfectly uniform. Don't make any joint narrower than 1/2 in.

As you pile up small pieces, try to use them as you go along or leave open spots to fill in later. Don't end up with them all in one section.

Working With Stone

The best bet for the amateur is to work one stone at a time. With this method you don't have to work like mad to get the stone down before the big batch of mortar you've mixed gets too dry. Don't start with stone that has very ragged edges. Don't use the flags as they come; many will be too large. Figure that the largest pieces you will put down won't be much more than 2 sq. ft. When you have a larger piece, crack it down the middle; the two pieces can be put together with a perfectly matched joint.

The best way to break stone is to place it on a hard, flat surface and use a broad chisel and firm hammer blows. Work the chisel along the line you've marked so that successive blows actually score the stone on the line until it cracks. It isn't difficult. Sometimes a stone won't crack the way you want it to, but that's part of stone working. Practice cutting on a scrap piece. If you hit too lightly the stone will never crack; if you hit too hard the stone will break where you don't want it to. Somewhere in between is just right— you'll get the feel of it sooner than you think.

Make a mortar bed slightly thicker than you need. Be sure the stone is clean. Run a damp rag over the surface that will con­tact the mortar and put the stone in place with a little twisting motion that will firm it in the mortar and assure contact over the whole area. Then use a rubber mallet and light taps to settle the stone further and bring it level with adjacent stones. Oc­casionally at the beginning you'll find a stone settling too low. When this happens, don't tilt the stone and scoot a little more mortar under it to raise it. Instead, remove the stone and the mortar and start over. You'll soon get the hang of putting down just the right thickness of mortar, so a few thumps with the mallet will settle the stone just right.

As you continue cutting and fitting the stone, you'll begin to accumulate a pile of smaller pieces. Try to use these as you go along; don't save them for last, or you'll wind up with an uneven pattern with all the small pieces in one section.

Check frequently with a level between adjacent stones, and just as frequently with the 2x4 across three or four stones. Don't try to fill the joints now; rather, as soon as the bed has set sufficiently, rake out the mortar in the joints and remove it. A pro may not do this, but an amateur will find it easier to go back later using a slightly stronger mix and, possibly, a finer sand.

Finishing Flagstone

After the stone setting is complete, go back where you started and, using a one part cement, three parts sand mix, fill in the joints. You can use the same sand you used for the bed, but a finer sand will make it easier to get smooth joints. Fill the joints in solidly and just a little bit high. If you're going to grind the floor, let the machine worry about bringing the joints down flush with the stones. If not, go back in five or ten minutes and cut the joints flush with a steel trowel. Clean off excess mortar right away before it has time to set.

To grind a floor you must rent a special machine that works like a floor polisher except that it turns grinding stones in­stead of brushes. If you lack experience, be sure to get full instructions from the place where you rent the machine. How smooth you get the floor depends on how much time you spend grinding. Protect the walls near the floor by draping them with heavy wrapping paper. After grinding, pick up all dust with a vacuum cleaner and then wipe with a damp cloth. A household vacuum cleaner may not pick up all the heavy dust left by the grinder. In this case, do the cleaning with a broom and shovel and then use the damp cloth. Let the floor dry thoroughly for at least a week before applying sealer and finisher.

Do the finishing with the special prepa­rations designed for this job. The man who sold you the stone will be able to furnish them. Chances are you'll need a sealer and finisher. The sealer plugs up the pores of the stone and the mortar joints. If the di­rections tell you to use two coats, use three. Allow proper drying time between coats. After both sealer and finisher are on and dry it's a good idea to give the floor a heavy application of paste wax.

After mortar bed is thoroughly set (but before it hardens) dig deep with a screwdriver or pointed hardwood stick. Minimum joint depth is 1 inch.

Clean out joints with brush and sweep up the residue. The bottom of each of the joints should be firm, not half-filled with old. crumbly mortar.

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