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Concrete and Flagstone Patio Tips

Concrete & Flagstone Tips

If you decide to try to build a brick patio like mine, you do not have to worry about the concrete finish. All that is important is that there are no high spots. Take your time and wiggle a board side to side across the forms you have built to create the shape of the patio. Low spots can easily be filled with more mortar. High spots will create a hump in the patio, unless you know how to sand a brick!

Flagstones are somewhat easy to lay. I prefer to install the border first. Remember to sort through the flagstones you have purchased. You are looking for the thickest pieces of flagstone. Ideally you should try to get a batch of flagstone that has fairly consistent thickness, but this is not always possible. The thickest piece of flagstone sets the tone for the amount of mortar that will be under each successive piece of flagstone that is installed. If you make a mistake and install a thinner piece of flagstone as your first piece, you will end up having a hump or a series of humps in your patio as you continue to install the stone.

Use a small torpedo level to make sure that the flagstones are not tilted. Lay out the stone to create the border. Do your cuts before you mix mortar. A rock hammer and chisel are used to score and cut flagstone. Have the manager at the stone yard demonstrate the easy way to cut and shape flagstone. It is not hard - it just requires a little practice. Chips that are generated from the cutting process can be used as filler in the mortar when you start to lay thinner pieces of flagstone. These thin pieces typically use up lots of mortar. The mortar for the brick laying is mixed as one part cement to three parts sand. When you place the flagstone into the mortar, tap the stone lightly to get it into position. If you have to tap more than three or four times, you have too much mortar under the stone. Too much mortar will also cause the mortar to ooze up in between the stones. This is not good as the intent is to grout the flagstone after they are all set. Once the border is complete, let the stones sit for 24 to 48 hours if possible. This will allow the mortar to get very hard. We need the stones to be set in place before we proceed.

Using a taut string line stretched between the border stone, you fill in the field. This is tons of fun. Just lay full stones that have been shaped to fit next to other stones. Use small stones to fill in gaps between large stones. You don't always have to try to chip a stone to make a huge jigsaw puzzle. If you want to fill in some of these larger "holes" between stones at the end of the project, that's OK. Don't forget to scrape out excess mortar that oozes out from under large stones from where the cuts go. If it dries and gets hard you will have problems.

Once the cut pieces are laid it is time to finish the grout. This is where you fill the spaces between the stones. This task is performed using a grout bag similar to what bakers use to decorate cakes. You mix up a soupy combination of one part sand to one part cement. The mixture should flow out of the bag with little or no squeezing.

It is important that no little rocks are in the mix. They will clog the nozzle. Over fill each joint by 1/4 inch. After a short period of time you will be able to scrape off the excess mortar without smearing the brick. Use a small triangular brick trowel for this job. The hard work will be worth it! It's best to do a small test pad to see if you are up to the task of doing an entire patio. Try it and see!

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2 Responses to Concrete and Flagstone Patio Tips

  1. I'm trying to find out how to estimate the amount of grout mix I will need. If I have the area dimensions, and am laying a flagstone walkway over sand. Is there a percentage of the area that is "typical" to use as the area between the slabs of flagstone? Also, if laying over sand, what thickness of grout mix would I need under the slabs?

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