When making a wood girder using 2" lumber, how many nails should be used for each layer and what should be their spacing?

The proper method for fastening wood girders involves using the correct type of nails and maintaining appropriate spacing to ensure structural integrity.

Using 10d nails provides the right length and holding power necessary for securing layers of 2" lumber effectively. The specification of 32 inches on center (o.c.) for spacing is a common industry standard for 10d nails in applications such as creating beams or girders, ensuring that the different pieces are adequately secured while allowing for slight movement due to expansion or contraction.

This spacing allows for the appropriate distribution of force and helps to prevent potential shear or withdrawal failures. It reflects best practices in carpentry and adheres to building codes, making it the optimal choice for this application.

In contrast, the other choices suggest either using larger nails, which may not be needed, or spacing that is either too close or too far apart for effective fastening in this context. Each of those alternatives either compromises the girder’s strength or does not align with standard practices in construction.