As previously mentioned porch posts are prone to rot at the base whether that’s at ground level or in this case where it meets the cill.

The post shown here also doubled up as part of the glazing frame. Posts invariably support a roof structure  as well therefore it is load bearing; this has to be taken into consideration when removing posts either whole or in part.

It’s vital that nothing goes ‘south’ otherwise extensive remedial work may well be required .

Once the glass has been removed, pit props are cut to length and fixed  and a measurement from a given point that is marked with a pencil to the ground next to the post to be removed is taken; this has to be accurate as it becomes the reference to any drop in the roof structure.

Next I use a mitre saw clamped to the post and make a  45degree cut. The saw should glide through without it binding if it binds then you know that the structure above is indeed going south.

Once removed a replacement can be offered up and glued  and clamped into place . When the glue has set enough the clamp can be removed allowing a router to machine a 12mm wide groove roughly 25mm deep to both sides of the joint so there are 4 grooves in total.

Into these grooves hardwood keys are fitted and glued these keys prevent any future slip in the joint . Once the glue has set I can safely remove the pit props and check the measurement I made prior to removal of the old post it should be exactly the same this indicates that no movement has occured.

One of the issues with part replacement of a post rather than a full replacement can be the dimensions of the old post and the dimensions of timber stock available for the replacement piece, an example would be a 1930s post which is 102 mm square incidentally the 2mm is probably the thickness of a century’s worth of paint.

The dimension in 1930 of a 4″ (100mm) sawn piece of wood would have been a readily available stock size but today 96mm x 96mm would be the closest readily available stock size.

So because of a 4mm discrepancy a choice of 6″ (150mm ) x 6″ timber machined down to the required dimensions or two pieces that are 150mm x 75mm (6×3″) that are glued together then machined to size are the only options with off the shelf softwood timber however it is often the case that I can find a hardwood section at a full 100x100mm.