How to bolt structural timber to a shipping container

In this blog we are going to show you how to bolt structural timber onto your ISO shipping container, quickly and easily, and without having to make a single hole in your container. 

Once attached, the timber can be used as a basis for many additions such as a roof deck or building another structure off the side of your container such as a carport or shade structure.

This solution is ideal for more heavy duty applications, and where simply fixing a piece of timber to one of our plywood adapters using wood screws would simply not be strong enough. For an overview of different methods of attaching timber to a shipping container depending on how strong you need the solution read our recent post.

Why use Domino Clamps as a fixing point for the timber? 

When building any weight-bearing timber structure, it’s important to start off with timbers which are straight, securely fastened, and parallel to each other.
This is why using a shipping container as a starting point can be so beneficial, as beginning with a large engineered steel box provides ballast for the structure to save on foundations, nice straight sides and a strong platform to work from. A few Domino Clamps securely fastened in the corner castings form easy mounting points for your structural carcass, or “first fix” timbers.

Without Domino Clamps, options for fixing timber using strong mechanical fixings such as set screws are limited as there are few places to bolt to a container. Drilling holes in your container’s box section edges is time consuming and seriously compromises the strength of the container, and the corrugated sides of the container are too flimsy to be used for structural timberwork. Besides, cutting any holes in your container will shorten its lifespan and can cause water to ingress, so having an alternative solution to this can add years on your container's life as well as not damaging its resale value.

Instructions

There are four M12 threads in the face of the Domino Clamp to bolt the timber to, but you may not feel your application needs all four. In the video we demonstrate this using just two of the threads diagonally across from each other.

1. Mark where the holes need to go onto the piece of timber you want to bolt to the shipping container.  The holes are spaced 100mm horizontally and 50mm vertically. Download the technical drawing and detailed instructions here.
2. Ideally using a pillar drill to make sure that the holes are cut accurately through the timber.  Pilot the holes and then finish off with a 12-13mm drill bit depending on how comfortable or snug a fit you want.
3. To ensure you are using the correct length set screws, measure the thickness of your timber and washer, add on 20mm for the Domino clamp, and then find a bolt fractionally shorter than that.
4. Alternatively, you can countersink the holes with a 25mm diameter countersink and use countersunk bolts. This will leave the heads flush with the surface of the timber.

When attaching structural timber along the length of your shipping container it may be beneficial to support it in the middle to prevent sagging or bowing, this is especially useful for a 40' container. Our roof brackets attach along the top of the long side of your container, and allow you to bolt your timber or steel section to the pre-threaded holes in the side, eliminating movement in the middle of the long section of material.

Shipping Container Brackets

We also have a range of shipping container brackets suitable for attaching structural timber to your shipping container.

The brackets will help you attach things to a container beyond what Domino Clamps can do by themselves by changing the size and position of the attachment point, as well as moving the attachment plane from vertical to horizontal.

Further Reads & Links:

• Find out how to frame your shipping container here or you can download our detailed guide for attaching a timber frame.

• Check our blog article introducing the different shipping container brackets to learn about their uses and find the right one for your project.