How To Work Out Roof Area For Soakaway

Okay that s the roof bit out of the way.

How to work out roof area for soakaway.

With the above information it is possible to work out how much insulation you may need how many roof vents you ll need to install and how many. Write this figure down on a notepad. So for our example the half roof area is as follows. For example 50m2 roof area requires a rubble filled soakaway of 50m 2 x 50 3000 0 3 2 8m 3.

Because this is only one half of the roof we will need to double this number to find the entire roof area 121 45m. To work out what size of soakaway is required you firstly need to calculate the area of the roof that will discharge into the soakaway. Depending whether the roof area is measured horizontally. The number of crates you need for a soakaway system doesn t just depend on how big your roof area is.

It affects walkability as well as drainage and roofs in areas of high rain or snowfall tend to have steeper pitches. So get your tape measure out and calculate the total surface area in square metres. Measure the length of the roof from one end to the other along the eaves. To calculate the size volume of a rubble filled soakaway the same calculation can be used but the result divided by 0 3.

The two determining factors for soakaway success are the size of the area or volume of water to be drained and the percolation rate of the soil sub soil or in some sites the depth to the water table. All soakaways must be sited at least 5m from any building or road and preferably at least 2 5m from any boundary. Calculating the roof area. In a prolonged downpour your roof will be taking 45 m2 of surface water and this will be going to your soakaway where else.

8 7m x 6 98m 60 73m. One of the first things to consider when choosing a site for a soakaway is the water table aka saturation line. How to quickly test if a soakaway will work. Roof pitch is a determining factor for cost of the roof as well as the roof area and the type of materials used.

And one cubic metre is suitable for 50 square metres of surface area. This is calculated as follows. You need to calculate the whole impermeable area roof size patio size driveway size etc as well as perform percolation tests to determine the permeability of the ground around the property.