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  • Writer's pictureJosh Lefebvre

How to Build a Valley using the RedX Roof App

Updated: May 22, 2021

There are several different ways calculate all of the measurements to build a valley. I’ll cover the most efficient method I’ve found, which uses RedX Roof App to automatically generate every measurement and angle to build your valley.

The app will create a valley plan, and automatically calculate

  • Ridge length

  • Every rafter length

  • Sleeper Board length

Here is what the plan will look like

valley builder calculator redx roof app rafter

Inputing Measurements

My app is set to use roof pitch but if you prefer in the settings of the app you can also change the app to use roof angles instead example 26 degrees.

Here are the measurements we need to enter in the app

Roof pitch that the ridge sits on:

This is the roof pitch of the roof that the ridge sits on.

Valley Roof Pitch:

This is the other roof pitch, the roof pitch of the valley you are doing(the blue rafters on the image below.

Height of truss:

Have a look at the image below

Rafter Spacing:

This is the spacing from one rafter centre to the next rafter centre (marked on the lower image as truss spacing)

Sleeper Board Thickness

This is the thickness of the sleeper board(colour red on the image below) For example the thickness of a 2x6 would 1 & 1/2 inches.

First Rafter Center (Optional)

Optionally you can set the first rafter centre, this measurement will determine the location(layout) of all other rafters. Keep in mind this measurement can NOT be bigger then the rafter spacing minus half of the rafter thickness. For example if your rafter spacing is set to 16" then this measurement could not be bigger then 15 & 1/4 inches.

You can use the image bellow to help understand where we are getting all of our measurements from.

Build valleys fast and easy with a valley calculator from redX roof app.

Measurements The App Will Give You

With these measurements entered into the app, the app will automatically generate a plan of the valley, with all of the measurements and angles needed. (Keep in mind that the app is also compatible with Centimetres and Millimetres)

redx roof valley framing over build
Valley Plan

valley builder ridge length cut list how to framing
Cut List

valley framing rafters cut list red roof app

Save And Load Jobs

Now that you are done creating your valley let's go over how we can Save and load your jobs to the app for later use.

Saving a Job

Tap on the Save this Job button just above the valley plan, then tap on Name This Job to add a name. After that tap on the Save button!

Loading a Job

Tap on the Load A Job button just above the valley plan, then select the job you want to open and then tap on Load.

Print and Share The Plan


Tap on the Print button just above the valley plan, then select the printer you would like to print to.

Export as PDF

Tap on the Share button just above the valley plan. This will create a PDF version of the plan that you can share with other apps. For example you can save the PDF to your phone, email it, or send it in a text.

Save To Photos

Tap on the Save To Photos button just above the valley plan. The app will ask you permission to save the plan to your photos, tap on accept and thats it! The plan will have been saved to your photos.

Installing The Rafters

  1. We will start by installing the ridge (colour yellow). If your first truss is level, then when you install your ridge it will automatically become level as well. Make sure it is centred properly. I also recommend marking where all of your rafters will go on top of your ridge, it's easier to do it now before its installed.

  2. You will install both sleeper lay-in boards (colour red).

  3. We will install our rafters, I like to start with the longest rafter and work my way up. Since we marked the top of our ridge where our rafters will go, nail the top of the rafter and if done correctly you shouldn't have to mark where the bottom of the rafter goes, just line up the bottom of the rafter with your lay-in board. Do the same for all other rafters. Also make sure that your ridge board stays straight when you are nailing your rafters.

Thats it your done! It should look like this.

framing a valley using the redX valley calculator


This is the fastest way to build these valleys. You can pre-cut every piece on the ground safely, you don't have to measure anything the app gets every measurement.

The bigger the valley the more time you save.

There are lots of other great features like Hip Rafter Builder, Hip Rafter Calculator, Turret Roof Builder, Plywood Angles, Dormer Builder and others...

Do you think this is something that you would use? Let me know in the comments.

Thanks to all of you who made it this far!

Now let's get back to work!

3,955 views1 comment

1 Comment

Aug 09, 2022

Many homeowners want to do the work themselves in order to save money.But in reality, it's probably going to cost you even more if you rely on amateur work. That's why it's better to hire roof repair plantation as soon as possible.


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