Preparation
There are a range of options available, so before selecting yours you’ll need to know the width between your joists and the height from the underside of the ceiling to the floor. Once you’ve got these measurements, bring them into Mitre 10 and select the style that’s right for your space.
The best and simplest way to install them is by slotting the unit in-between existing joists/rafters/trusses. Most joists will be spaced at a minimum of 600mm, providing you with an ideal space to install them.
Positioning is also very important:
- Choose a location that will give good headroom at the top of the stairs.
- Make sure you have good access at the bottom of the stairs for free movement around them when they’re folded down.
- Allow for the operation of the stairs, as they require a greater space to open than indicated by the opening in the ceiling.
Framing
Choose the location you wish to install the stairs. If possible climb into the roof to see exactly where the joists/rafters/trusses are situated. You’re looking for trusses to attach one side of the stairs to, and to build your framing off . Try and choose an area that’s under the highest part of the ceiling to give you as much room as possible when you climb up the stairs.
Once you’ve chosen the area in the roof you want your stairs to be installed, drill some reference holes through the ceiling in the four corners of where your framing will be located.
Use the instructions provided to determine the size of the opening, and use your reference points to mark the area where your opening in the ceiling will be. Use a rafter square to make sure the area is perfectly square.
Cut out the ceiling plasterboard with a multi-tool. If you need to cut through any ceiling batons, that’s fine as they’re generally non-structural.
Frame out between the trusses to the size provided in your instructions. You’ll need to pack any gaps between the plasterboard and the trusses, screwing them into place with 75mm self-tapping screws.
Fix the plasterboard to the new nogs with 32mm drywall screws.
Installing the stairs
Predrill any necessary screw holes as per the instructions for your particular set of stairs.
To screw the stairs into the frame you’re going to need to hold the stairs securely in place. An easy way to achieve this is to make yourself a set of cleats. To make these, cut a small length of timber, and screw them into the framing. You’ll need 2 on the hinge end of the hole, and 2 on the sides approx. 150mm from the non-hinge end. Turn them so they’re flush with the hole, and ready to turn 90° to hold the unit once it’s been lifted into place.
When the unit has been lifted into place and is sitting securely on the cleats, pull down the first step of the stair so you can screw it in place through your pre-drilled holes.
Screw in the back plate first, making sure the bottom of the unit is sitting flush with the plasterboard.
Screw in the sides, but don’t tighten them completely yet.
Remove the cleats that were holding the unit in place.
Shut the unit and check that it looks even, and is parallel to the framing. To make adjustments simply tighten or loosen the two screws on the sides.
Pack any gaps between the unit and the framing with wedges.
Check that the packers haven’t moved the unit, and that the door shuts properly. Make sure all screws are tight.
Cut stairs to length. The stairs are designed to be longer, so you can cut them to fit perfectly.
To do this, fold the stairs down and unscrew the last section of treads. Using a straight edge, place it along the top side of the stairs and slide it down until the straight edge hits the ground. Mark the straight edge at the bottom of the middle stair section and transfer this distance onto the bottom section of the stairs.
To cut the bottom of the steps to the same angle as your floor use a sliding bevel, or lay a straight edge on the floor and transfer the angle onto the stairs.
Cut stairs using a handsaw.
Use a small planer or sandpaper to place a slight arris on the cut edge, this will stop the stair from splitting when they hit the ground.
If you want to, you can fit architraves or trim around the opening, or you can choose to plaster it to be fl ush with the roof.
