EXCAVATION CALCULATION BASIC INFORMATION AND TUTORIALS

Excavation is measured by the cubic yard for the quantity takeoff (27 cf # 1 cy). Before excavation, when the soil is in an undisturbed condition, it weighs about 100 pounds per cf; rock weighs about 150 pounds per cf.

The site plan is the key drawing for determining earthwork requirements and is typically scaled in feet and decimals of a foot. There is usually no reason to change to units of feet and inches; however, at times they must be changed to decimals. Remember that when estimating quantities, the computations need not be worked out to an exact answer.

Swell and Compaction.

Material in its natural state is referred to as bank materials and is measured in bank cubic yards (bcy). When bank materials are excavated, the earth and rocks are disturbed and begin to swell.

This expansion causes the soil to assume a larger volume; this expansion represents the amount of swell and is generally expressed as a percentage gained above the original volume.

Uncompacted excavated materials are referred to as loose materials and are measured in loose cubic yards (lcy).When loose materials are placed and compacted (as fill) on a project, it will be compressed into a smaller volume than when it was loose, and with the exception of solid rock it will occupy less volume than in its bank condition.

This reduction in volume is referred to as shrinkage. Shrinkage is expressed as a percentage of the undisturbed original or bank volume.

Materials that have been placed and compacted are referred to as compacted materials and are measured in compacted cubic yards (ccy). Bank, loose, and compacted cubic yards are used to designate which volume we are talking about.

Figure 9.1 is a table of common swell and shrinkage factors for various types of soils. When possible tests should be performed to determine the actual swell and shrinkage for the material.

FIGURE 9.1. Swell and Shrinkage Factors. (Solid rock when compacted is less dense than its bank condition.)

WALL TILING AND TILE GROUTING BASIC TUTORIALS

What Are The Different Types of Wall Tiles and How To Install Wall Tiles?

Glazed Wall Tiles ~ internal glazed wall tiles are usually made to the various specifications under BS EN 14411: Ceramic tiles.

Definitions, classification, characteristics and marking.

Internal Glazed Wall Tiles ~ the body of the tile can be made from ball-clay, china clay, china stone, flint and limestone. The material is usually mixed with water to the desired consistency, shaped and then fired in a tunnel oven at a high temperature (1150 deg C) for several days to form the unglazed biscuit tile.

The glaze pattern and colour can now be imparted onto to the biscuit tile before the final firing process at a temperature slightly lower than that of the first firing (1050#C) for about two days.

Typical Internal Glazed Wall Tiles and Fittings ~ Sizes † Modular 100 x 100 x 5 mm thick and 200 x 100 x 6„5 mm thick.

Non-modular 152 x 152 x 5 to 8 mm thick and 108 x 108 x 4 and 6„5 mm thick.

Other sizes † 200 x 300, 250 x 330, 250 x 400, 300 x 450, 300 x 600 and 330 x 600mm.

Fittings † wide range available particularly in the non-modular format

Bedding of Internal Wall Tiles ~ generally glazed internal wall tiles are considered to be inert in the context of moisture and thermal movement, therefore if movement of the applied wall tile finish is to be avoided attention must be given to the background and the method of fixing the tiles.

Backgrounds ~ these are usually of a cement rendered or plastered surface and should be flat, dry, stable, firmly attached to the substrate and sufficiently established for any initial shrinkage to have taken place.

The flatness of the background should be not more than 3 mm in 2„000 for the thin bedding of tiles and not more than 6 mm in 2„000 for thick bedded tiles.

Fixing Wall Tiles ~ two methods are in general use:-

1. Thin Bedding † lightweight internal glazed wall tiles fixed dry using a recommended adhesive which is applied to the wall in small areas 1 m2 at a time with a notched trowel, the tile being pressed into the adhesive.

2. Thick Bedding † cement mortar within the mix range of 1 :3 to 1 :4 can be used or a proprietary adhesive, either by buttering the backs of the tiles which are then pressed into position or by rendering the wall surface to a thickness of approximately 10 mm and then applying thin bedded tiles to the rendered wall surface within two hours.

Grouting ~ when the wall tiles have set, the joints can be grouted by rubbing into the joints a grout paste either using a sponge or brush. Most grouting materials are based on cement with inert fillers and are used neat.

Note: The alternative treatment at edges is application of a radiused profile plastic trimming to standard spacer tiles.