Wiki: Loft Hatch Install

==Cutting a joist== Loft floor joists are generally spaced too closely to leave space for a practically sized loft hatch, so one joist is cut away to give enough space for the hatch. This is done as so: # check there isn't a major load sitting on only the joist to be cut, or 2 joists, such as a water header tank. # screw temporary crosspieces as in diagram B # cut the middle joist # fit crosspieces as in diagram D

==Diagrams==

1 = original loft floor joists 2 = newly added timber, same size as joists 3 = temporary pieces to hold the joists still during work 4 = Lining to fit

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

A. Before

1 1 1 3333333333333333 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3333333333333333 1 1 1

B. Add temporary supporting cross pieces

1 1 1 3333333333333333 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3333333333333333 1 1 1

C. Cut joist

1 1 1 3333333333333333 1 1 1 12222222222221 1 1 1 1 1 1 1 1 1 1 12222222222221 1 1 1 3333333333333333 1 1 1

D. Add crosspieces

1 1 1 1 1 1 1 1 1 12222222222221 1 1 1 1 1 1 1 1 1 1 12222222222221 1 1 1 1 1 1 1 1 1

E. Remove temporary bracing

1 1 1 1 1 1 1 1 1 12222222222221 14444444444441 14 41 14 41 14 41 14444444444441 12222222222221 1 1 1 1 1 1 1 1 1

F. Add Lining

Job done.

==How its done== Temporarily support the joist that will be cut. This can be done by laying 2x4 down flat over 3 joists, and putting a long [[screw]] or 2 in at each point. Its possible to omit this support, but not recommended, the ceiling is likely to break up from the sawing etc.

Make the 2 [[saw]] cuts in the joist.

Now 2 lengths of joist sized timber are fitted across to support the 2 ends of the cut joist. These also act as 2 sides of the loft hatch hole. 2x 4" [[nails]] at each point will do the job, total 12 nails. Large screws are also an option, a bit more work but less ceiling damage likely. If you have big 2x8 timbers spanning a large disance, 3 nails at each point would be better.

Fit lining timber round the interior of the hole. 0.5-1" planed timber is good. Line the bottom of it up with the level of the ceiling.

Fit timber moulding to the underneath surface where the lining meets the plasterboard, mitring the corners.

==Tips== Its good to have headroom above the hatch.

A loft hatch can be made long and thin if preferred, so that 4x8 sheets can go up.

Sheet the landing and close the bedroom doors, it'll be very messy.

The loft ladder, if fitted, is best screwed through the lining and into the joists.

You'll need [[filler]] or plaster to make good ceiling damage around the hatch.

Joist hangers are also an option to support the new crosspieces.

Taking care to get the hatch properly square makes life easier.

Don't forget to insulate the hatch itself, and to trim the [[insulation]] slightly at the opening edge so it opens ok. Draught excluder is also well worth having.

Another variation is to make the frame out of 2x4, hang the hatch/door on it, then fit the whole thing to the surrounding joists. This is a good option if you're fitting a ready made insulating loft hatch set.

Melamine coated chipboard makes a good general purpose loft hatch, as long as you have the equipment to cut it clean & square.

==See also==

[[Strengthen a Wood Floor]]

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