Bearer & Joist calc\'s summary 09 PDF

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Bearer & Joist Calculation Summary:

Bearers: Note: Building width = measurement from outside of wall frame to outside of wall frame.

Bearers L – Shape:

Do these calculations separately, and then add the totals together. Use sketch opposite for reference.

1. Split building into two sections, long side and short.

2. Area 1 =

3. Area 2. =

4. Use answer of both above to establish timber order, remember joins in timber lengths should suit bearer centres. As per specification.

Joists:

Remember internal room sizes are used for calculating joist quantities. So from most plans you will have to deduct wall thicknesses, more importantly LOOK at dimension lines and measurements. Specific formula shown over page.

M. Martin / 1st Year Trade / Maths / Bearer & Joist Calc’s summary 09

= Number of joist for straight room as above.

Joists for L-Shapes:

Note: As for bearers, split the room in half. You will calculate the long joists first, then the short. Paying close attention to additions of external joists, DON’T double up.

1. Calculate number of long joists with the following formula.

2. Calculate number of short joists with the following formula.

3. Use answers above to establish a timber order, remember joins are relative to bearer spacing’s...