To build an outdoor countertop the first requirement is a suitable support system. This can be a brick pedestal or metal framework or any other system that is considered water and heat resistant. An outdoor countertop must have a sturdy base made of a weather resistant 1-1/2" thick lumber such as douglas fir, redwood or cedar. The base must be secured to the support system and this can be accomplished by using lag bolts with drilled anchors. be sure the base is secure and the countertop assembly will go smoothly.
Begin by determining the desired size of the countertop and the desired finish which may be ceramic tile or brick paver tiles. It is not advisable to fabricate an outdoor counter top using any laminate finishes since these are normally constructed using a non heat or water resistant plywood underlayment.
A countertop may be fabricated in a shop and transported to the site. However if using tile or brick pavers as a finish it is advisable to fabricate the top on site and in place.
For the base cut pieces of the treated lumber to length. The number of pieces needed will depend on the desired width of the countertop. Attach the base pieces to the below counter support and size the base to approximately 1" under the desired size of the finish top. This will allow for a finished tile skirt to be installed around the edges of the countertop.
Where ceramic tile is desired attach strips of 1/2" plywood as skirts to the base and install these to 2" above the top of the base. This will be the total thickness of the tile and mortar bed. Cover the base with two layers of building paper and wire lath. Secure the paper with 1/4" staples and secure the wire lath with #3 galvanized nails. Mix a mortar bed using 2 parts sand, one part cement and 1/4 part lime. Float the mortar bed even with the top of the plywood skirts. Allow the mortar bed to dry completely before removing the plywood skirts.
Next lay out the ceramic tile in the desired configuration and design prior to using any adhesive. Make all edge and end cuts and ensure the pattern, tile spacing and design are correct. Install the tile by applying tile mastic to each tile and placing it on the mortar with a subtle side to side motion to ensure a thorough contact. Tile spacers may be used to ensure all spaces are similar however this is not necessary.
Once the tile top is installed layout for the countertop face tiles and cut these pieces. A mitered or beveled corner is preferred and be sure to leave a similar spacing between these tiles as the countertop tiles. This will ensure a uniform appearance. For the grout filler use only a sanded type grout since this is far more lasting and weather resistant than a non sanded grout.
Mix the grout to medium consistency and apply it to the top and sides with a sponge type trowel. Allow the grout to dry for at least two hours before washing the excess away with a damp sponge. Polish the tile and grout with a soft cloth and apply 2 coats of grout sealer to the entire countertop and edges. Allow the sealer to dry completely between coats.