On 29/05/2012 11:01, fred wrote:
On Friday, May 25, 2012 7:38:04 PM UTC+1, John Rumm wrote:
On 22/05/2012 20:18, The Medway Handyman wrote:
SWMBO wants some raised beds made, railway sleepers or similar.

They are going on an area which is currently slabbed with those
attractive 70's pink& yellow slabs - which will be removed.

Carpentry no problem - but should raised beds be lined with
anything?

Not worried about the timber rotting - it will be pressure
treated. More moisture retention.

ok, I had a bash at some yesterday:

http://wiki.diyfaq.org.uk/index.php?...ed_flower_beds

Had planned on doing them with a single length of 9x2 for each
side, but the timber shop did not have that in long enough lengths.
So I bought 6x 4.8m lengths of 6x2" in the end. (got about 2.4m
left over). Also used about 2m of 3x3" fence post for the corners.

Prolly took about 3 hours including getting the timber. Timber cost
£120.

Well I'm not really a believer in raised beds per se but I would
think you might have been better overshooting the ends and putting
the vertical post outside the rectangle. All the forces are going to
be trying to push the sides off so your way you are depending on the
nails to hold it together. Setting the posts outside would allow the
post be anchored in the ground to help resist the outward forces.

Yes that is a fair point, although there is not going to be a huge
amount of force involved. Although the article did not actually make it
that clear (I may go and "improve" it) the direction of the "lap" at the
end was significant, since it means the long sides are nailed not only
to the face of the support block, but also pinned through ends of the
short sides, meaning to move them away from the blocks you would need to
shift not only the nails into the face, but the nails acting in shear
into the ends of the boards.

For fixing in place, what I have seen done, is to drive a few bits of
rebar into the ground on the inside adjacent to the sides, and then fix
that to the side of timber with a bit of builders band and some screws.
A bit easier to do than attempting to "plant" the whole post section.

(for the record, I did consider more elaborate joinery at the corners -
possible half lapping each plank and then pinning down through the
overlaps - but in the end rejected that since with 6x2 it would have
taken very long fixings, plus another 32 cuts to prepare all the ends!)

Just my tuppence worth.

Valued, thanks.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/