Material estimation for blockwork, brickwork, paving, cladding, etc

Published by Strada Imaging on

Modular elements are integral to civil construction; bricks, blocks, and tiles are some of the examples. Such repeatable, off-the-shelf elements span areas of structures, enabling fast building and finishing operations. Made out of concrete or cement, blocks can be solid or hollow, the latter enabling lightweight construction. Similar paving blocks and cladding can span very large areas. Due to lead-time and on-site storage considerations of these materials, mainly for blocks and bricks, estimating their quantities accurately is paramount.

Figure 1. An area of a structure with modular elements and openings

The area needed for these modular elements has to be calculated first. These areas can be calculated by subtracting the areas of openings from the overall extent, as shown in Figure 1. There is also material wastage involved, requiring more material than that is indicated by area calculations alone, e.g. 5% wastage area-wise. This area is useful for quantity surveyors, buyers, and site engineers.

Once the area required is known, based on the height and width of concrete blocks, bricks, paving stones, or cladding panels, the area covered by a modular element can be estimated. The two values lead to the calculation of the number of blocks or panels required. Usually these elements come in a pack and knowing the number of units in a pack, the packs that need to be ordered can also be evaluated. This information is again sought by the site team and the buyer.

A module, called Blockwork, Cladding, and Paving within GroundApp helps site personnel and the buyer easily perform this calculation. It allows the user to calculate calculate overall area, areas for openings, and then the net area, based on the wastage input by the user. Then it allows the user to choose element type (e.g. block or bricks), allowing the calculation of number of units needed. Moreover, the user can input the amount of units in a pack to calculate the amount of packs needed for the job.

Figure 2. External cavity wall construction

Figure 2 depicts a cavity wall, where facing bricks, substructure blockwork, and insulation are all made out of repeating module structures. For such a wall, the Blockwork, Cladding, and Paving module has the dimensions of bricks and blocks, leading to the quantity calculations and an estimation of their respective packs. Similarly insulation also consists of a number of panels. The Blockwork, Cladding, and Paving module also permits definition of custom element sizes, and this feature can be used to define the insulation panel size, and based on the total area of insulation required, evaluates the panel numbers.