Staircase Installation Guide

Your stairs are an integral part of your home’s interior, designed to last for many decades, so you must get your staircase installation spot on. 

Our stair specialists here at Stair Crazy have produced this helpful guide on how to install stairs, which explains the ins and outs of fitting a flight, and how to do it correctly from start to finish.

Fitting a staircase

1. Measure your space

First of all, you’ll need to work out how much space you have to play with. Measure the floor-to-floor height with a metal tape measure, which is the distance between the lower and upper floors. This will help you work out how many steps you need, which we’ll get on to in the next section.

Next, measure the width of the area. Standard domestic stair widths are about 800-900mm, which is enough space to comfortably fit the staircase and balustrade while leaving enough room to walk.

2. Determine the rise and run

Next, decide on the rise and run of your stair flight - the rise is how high each step is, and the run refers to how deep each step is. 

You should aim for a rise between 170 mm and 200 mm, which is typically the most comfortable for people walking up and down your staircase. 

You can now work out how many steps you’ll need by dividing the floor-to-floor height by the rise per step.

The run, also known as tread depth, should be between 250mm and 280mm.

3. Choose your staircase type

This is where you can really start imagining how your dream stairs will look in your home. There are numerous types of staircases to choose from, including straight, L-shape, U-shape, turned, and more.

Be sure to consider the layout of your interior, available space and your budget before making a decision, as not all flight styles will be suitable for your property.

4. Prepare the opening

After you’ve decided where your stairs will be fitted, you’ll need to install structural joists to support the flight. Fit a strong, durable header across the opening to hold up the floor and prevent sagging.

To reinforce the sides of your staircase, anchor trimmer joists at the sides of the stair opening to carry the weight from the floor joists that were cut to accommodate your stairs. Trimmer joists are usually doubled for extra strength.

Be sure to use robust metal hangers, nails and screws to anchor the header and joists, as this will keep the structure secure and safe. Additionally, make sure the trimmers are supported at both ends using the wall, a joist hanger or another support beam.

5. Install the stringers 

Now, for the ‘backbone’ of your staircase frame: the stringers. These are the sloped boards that sit at the side of your steps to support them. 

Using the number of steps calculated and the rise and run measurements from earlier, mark the step pattern down the board, which should look like a zig-zag. This pattern shows where each step will sit. 

Cut along the lines using a circular saw and install the finished piece in position, checking that the rise and run line up perfectly, and the bottom end sits flat on the floor.

6. Install the treads and risers

Next, it’s time for the steps, which are made up of risers (the vertical parts) and treads (the horizontal platform you actually step on while using the stairs). Our experts recommend building from the bottom upwards, as this will help to keep the stairway aligned, as each riser is designed to hold the tread above. 

Cut the riser boards to slot neatly into the vertical cuts of the stringers. Apply a good-quality wood adhesive to this section of the stringer, and fix the riser in place securely using screws or fixings.

Cut the treads to fit between the horizontal cuts of the stringer boards. Again, apply wood glue to the tops of the stringer notches and place the tread above the first riser, screwing or nailing it into place using sturdy fixings. Typically, the end of the tread will jut slightly over the riser to provide a wider platform for people to step on.

Repeat this step all the way up the flight.

Top tip: always use a spirit level to ensure your steps are perfectly level. Otherwise, your stairs could become a trip hazard and won’t look great.

7. Add your balustrade

Your balustrade, or bannister, is the safety structure that runs parallel along your flight and landing to prevent falls down the edges.

It consists of:

• Newel posts - Large pillars at the top and bottom of the balustrade that help to support it.

• Handrail - The long rail you hold when moving up and down the stairs.

• Baserail - Sits along the ground and holds your spindles in place.

• Spindles - The vertical columns that sit between the base and handrails.

Step 1: Install the newel posts first, either to the floor or joists, using bolts or screws. 

Step 2: Attach your baserail to the edge of your treads, stair stringer or the edge of your landing, parallel to your handrail, using screws.  

Step 3: Install the spindles (balusters). Mark equal spaces along the baserail by following the ‘baby head rule’ - the gaps between each should be no more than 10cm for safety reasons. See our spindle spacing guide for more information. Then, use a mix of adhesive and screws to fix each solidly into position, creating a stable barrier to prevent accidents and falls.

Step 4: Fit the handrail. Simply measure the distance between each newel post and cut it to fit before attaching it to each post and above the spindles. The handrail height must be 900mm to 1000mm from the edge of your treads according to the building regulations set out in Approved Document K - Protection from falling, collision and impact. You can find out more about handrail requirements in our blog ‘Are handrails required for houses and flats?’.

By following this guide, you’ll be able to build a resilient flight of stairs that will stand the test of time and look excellent for years to come.

Premium parts for staircase installation

Looking for excellent quality timber or metal stair parts for your staircase installation project? We can help you there - at Stair Crazy, we only supply top-grade components in a wide range of materials, including real oak, white-primed timber and metal. 

Speak to our team today for product queries or recommendations!