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Valley lay board

valley lay board

We often get asked questions about valley lay boards here at Build4less.

A typical question we would receive would be something along the lines of the following:

I am creating a new roofing extension. My structural engineer specified that I should join my new roof to the old using layboards, this method is new to me, what is the best technique for cutting and joining the layboard?

Well, first we need to answer the question:

What is a valley lay board?

A valley lay board is made by pitching a roof then building another roof on top of it. Rather than having a valley rafter intersect them equally, you build a primary roof and then the next one lies over it

How to cut, mark and fit valley lay boards

We found it is easier to show how to do it rather than try to explain it in words.

Fortunately for us, Robin Clevett has put together a great video that shows how to mark, cut and fit valley lay boards

This video is extremely helpful for anyone who is looking to add a valley lay board to a new roof extension. The step by step instructions are clear and concise, and I would definitely recommend this video to anyone who is looking for help with this particular task.

Robin starts off by explaining what a lay board is and when you would use it.


He then moves on to explain in great detail how he would mark up his lay boards, including all the tools required for this process

Robin then explains the cutting process of the valley lay boards, including how he cuts the edge bevel on the bottom.


He then shows us the tricks he uses for marking up and measuring the existing roof


Robin then moves onto how to mark out and cut your lay boards.

Finally he shows how the valley lay board should be installed, nailing it in place securely

Adding a valley lay board to a new roof extension can seem like a daunting task, but this helpful video shows step by step how it's done.

The video is well-made and easy to follow, and you should be able to complete the task with no problems. I would definitely recommend this video to anyone who needs to add a valley lay board to their roof extension.