Loft hatch casting and cover
Once you have the rough sawn timber loft access hole through the ceiling, you need to fit the casing using planed timber to form the finished access. Exactly how you do this will depend on the type of hatch you are going to have. The three typical styles are:
- A simple drop in, lift up hatch.
- A hinged hatch swinging up into the roof space.
- A hinged hatch swinging down - this is typically required where a loft ladder is fitted to the ceiling joists.
However, whichever style is used, the general principle is the same, use planed timber to make the surround - this does not need to be too thick (typically 18mm/¾ inch should be fine) but the width needs to suit the style of hatch and the differing needs for the position of the cover when in place - see below.
Start by measuring two opposite sides of the frame in the ceiling and cut pieces of planed timber to suit.
In turn, offer up each cut length of timber, position it so that the lower edge is in line with the underside of the ceiling and fix it in place using two or three wire nails - do not drive the nails home, if you need to subsequently make any adjustment, having the nail heads exposed will make this easier.
Now measure the two remaining opposite sides of the frame in the ceiling and cut pieces of planed timber to suit.
Now in turn, offer up each cut length of timber, position it so that the lower end is in line with the underside of the first two planed timbers nailed in place - check that the bottom edge of the new timbers are in line with the underside of the ceiling - if not, you will need to adjust the original pieces of timber. When all the pieces of timber and the underside of the ceiling line up, fix the new pieces of timber in place using two or three wire nails. Finally drive all the nails home, if necessary use a nail punch to drive them below the surface of the timber.
Finish off the underside of the hatch by measuring each of its sides and cut four pieces of architrave with mitres at each end to suit - allow them to sit slightly away from the internal face of the casing and nail them to the underside using wire nails - then put a wire nail through the meeting corners so that adjacent pieces are attached.
Different hatch styles.
1. A simple drop in, lift up hatch.
The width of timber used to make the casing is not really important as the hatch cover just sits on top of it. The lower edge of the casing is in line with the underside of the ceiling.
2. A hinged hatch swinging up into the roof space.
The width of timber used to make the casing needs to be such that the lower edge is in line with the underside of the ceiling while the top edge will support the cover in line with the hinge.
To make the job easier, two other options are:
- Use thicker timber for the casing all the way up the joists, then fix an inner frame of narrower planed timber to support the hatch cover after the hinges have been fitted to the cover and joists - this does slightly reduce the size of the access.
- Use timber to form the casing as described with the top edges the appropriate distance down from the hinge position to suit the thickness of the cover and make any adjustment required by packing or trimming when fitting the hinge between cover and joist.
3. A hinged hatch swinging down - this is typically required where a loft ladder is fitted to the ceiling joists.
The width of timber used to make the casing is no really important as the hatch cover when closed will hide it - the only thing to remember is that it needs to be wide enough to take the hinge and a small beading around the top of the closed cover to prevent draughts - fit the beading after the hinged cover has been fitted.
The hatch cover.
To make the hatch cover, just cut a piece of 3mm (1/8 inch) plywood to the size of the hatch (less 6mm (¼ inch) on each dimension to give clearance) and edge it with 25x50mm (1x2 inch) planed timber. You could use a thicker piece of plywood without the timber frame where the hatch cover is a simple 'drop in' style, but the timber frame is really required where the cover is hinged and you need something to fix the hinges to.
Once made, a 'drop in' cover can be used straight away - for hinge covers, offer up the cover to the hatch and fix thehinges (and a catch if required) to suit.