I need to replace a gate and want something smarter than a treated
softwood one so am looking for advice on what timber to use. I found a
picture of exactly the sort of thing that I had in mind here:
This is obviously oak, but would I use green or seasoned oak to make
something like this?
I've never made anything that would be exposed to the weather like this
- presumably I need to worry more about the expansion and contraction of
the wood. If I used 6" wide seasoned planks for the front face of the
gate is it going to expand and deform/split when it gets wet?.
Any advice greatly received or ideas of a book that might help me with this.
many thanks, John
Yup. Use seasoned. leave outside a few weeks, and use T & G.
Also bolt together if possible. with galv. bolts. Or use recessd galv
screws and cover holes with wood plugs.
Mortice and tenon and BOLT or PEG the diagonal and the frame.
I have wood place the sells me stuff for this purpose.
Done many oak doors in T & G..
On 6 Mar, 11:58, email@example.com wrote:
Tongue & groove is too thin and fragile for outdoor use, unless it's
so big that it will look clumsy. You're better with half lapped
rebates instead. It's also easy to cut rebates with DIY hand-tools,
but grooving is more troublesome.
Sweet chestnut is good, if you're in the right part of the country.
Oak is good too, but it makes for a heavy gate. It also needs more
effort to cut mortices. Easier if you work it green. Remember that oak
will stain with iron, so use stainless fittings, bronze nails, and
shim beneath hinge plates with plastic. Otherwise let it darken.
Probably the best all round is larch. Try to avoid any that looks like
it's thinking of twisting. Some trees are more resinous than others,
and they'll be the best lasting. You can use any junk for the boards,
but try and select good stuff for the frame.
Douglas fir is easiest to find, but not terribly rot-resistant. Larch
is better, and otherwise similar.
That's a door rather than a gate: taller than wide, meaning that so
long as you have adequate hinges, then the design is easier. For a
door like this, then just use three decent-sized hinges. Really a
ledged and braced door like this ought to be the other way round
anyway - put those diagonals into tension, not compression.
The difficulty with gates is that they're a long cantilever (i.e. they
stick out, and they're only supported from one end), so structural
design of them is non-trivial. If you're designing a wide gate then
think of it as a triangle rather than a rectangle - the forces are
largely that diagonal tension hanging down from the upper hinge, the
rectangle is just a filler panel. This is why it's good to place the
top hinge as high as possible, and to have an upstand above the main
gate at the hinge end, a bit like this:
Although really that top hinge ought to be mounted higher, above the
top rail. The main load is (or should be) in the diagonal, not the
In general, what you can get most easily. Although oak will likely be
over-priced unless you're dealing with somewhere that will have both,
then you can go for green and it will be less trouble to work it. One
of Aldi's bargain morticers would help.
Of course it will expand. It will do this because it becomes wet, no
matter how much you dried it beforehand. You don't even need to get it
"wet", just UK winter humidity will expand it. Read Hoadley's book
"Understanding Wood" or else the US Forest Products handbook to get
chapter on verse on all this. Shrinkage and expansion is accurately
predictable if you do the numbers. Unless it's "seasoned" for a decade
of cycles, then "dried" timber still keeps moving, it's just in a
different state when you first get it.
Generally though, wood shrinks 10% worst case from wet, or else
expands 10% from fully dry. It does this axially and
circumferentially, and not at all lengthways. For any more detail,
So carpentry for outdoor timber has to deal with this expansion.
Forget trying to fasten everything rigidly, it's not going to happen.
Be cautious anywhere near cross-grain joints (one piece shifts one
way, the other goes at right angles). Be cautious of butted long-grain
edges, as they're going to add the expansion of individual boards into
expansion of the whole door, causing it to stick. Try and absorb
expansion of individual pieces by how you arrange or joint that one
piece, before it combines up into several movement's worth.
Traditional designs, so long as they're reproduced accurately, are
usually the way they are so that they cope with this.
A simple approach is the ledged and braced door, as your picture. This
uses a Z-shaped structure of lengthways members (not expanding
lengthways) with vertical shiplapped boards to fill the hole. The
expansion is in the boards going sideways, so each board is nailed
once in the centre of it (i.e. three times over its length, but only
once per width) and it will expand and contract individually. The lap
between boards absorbs this seasonal movement and the overall door
remains the same size. Shiplapping (just overlaying board edges) is
most common, but looks a bit cheap. Better is to plane a half-
thickness rebate into the edge of each board ("up" and "down" on each
edge) and keep the boards fastened flat. The tool for this is a
Stanley #78 rebate plane, which you'll find on eBay. You can't do it
easily with a router, unless you have a big one in a table that can
cut a wide shallow rebate safely. When you set the boards, remember to
leave this expansion space (i.e. don't butt the rebates tight). Leave
about 5% gap (of board width) at the edge of each rabbet, or less if
you actually read Hoadley and do the numbers.
When making a ledged & braced door, the question is how to join the
diagonal braces into the horizontal ledgers. Butting is popular, but
gives a weak, flexible door. Best approach (for practical simplicity)
is a half-lap joint, then pegging it with wooden pegs - or screws
(don't nail the frame - peg or screw it. Nails are just for hanging
ther infill panels on.) Assemble the ledged frame flat on the ground,
pin a couple of battens on the vertical edges to hold it in place,
then drill through both halves of the joint. Take a treenail (square
oak or hard hardwood strip, just bigger than the hole diameter, shave
one end to a round point and then drive it into the hole with a
mallet. Saw the ends off flush. Decoratively, the diagonal is often
thinner and lapped beneath the ledgers at both ends.
More sophisticated doors use joinery, not carpentry. Joinery is the
high-tech medieval approach of "joining" panels, without them then
splitting with seasonal shifts (it's where the distinction in job
roles comes from). You make a more complicated structure on a bench,
with cut joints, rather than assembling unsquared beams on site (the
other role distinction). Joinery's basics are to make a rigid
structure of these long members (no expansion lengthways) with joints
between, then to fill in the holes with loosely placed boards that are
free to move. You'll get a more solid door this way, but it's much
more work. This is where the well-known six-panel door comes from, but
you'll be cutting a lot of mortices to make the frame. Twisty in
larch, hard graft in oak. Depends how much effort / result you want.
If you're going this far, read some books first.
Good books on this topic are old mid-century handbooks of carpentry,
especially Charles Hayward's series (eBay again).
Thanks for the extremely comprehensive reply. You're right I meant door
Just a few more questions below
Andy Dingley wrote:
I'm in Hampshire. I know that the local sawmill does occasionally have
some chestnut so will have to make a visit.
Do you know any good online suppliers of bronze nails? I've never seen
them around here.
What the reasoning behind? Is there an advantage to them being in tension?
I've never worked with green oak before is it much easier to work with
I've got a morticer and router in a table so the joints and rebates for
the planks on the front of the gate shouldn't be too much of a problem
especially if green oak is easier to work with than seasoned.
I was slightly confused by this description. I was planning to use
mortice and tenon joints to join the verticals to the the horizontals
then just butting the diagonals in and nailing the planks to the front.
I understand how a half lap joint would be an improvement for the
diagonals, but won't it interfere with the mortice and tenon?
I like the idea of using wooden pegs - I'll have to experiment.
many thanks for all the help,
Boat chandlers. I get mine from Robbins in Bristol. They're not cheap
though! Stainless is cheaper, but I do like the look of bronze with
oak. Mostly (I'm doing indoor furniture) I actually use cheap copper
roofing nails as rivets in drilled holes through fumed oak.
It's arguable. Mostly an issue for big stuff anyway, so a garden gate
or door is neither here nor there. Theoretically it's stronger with
tension, but there's also an argument that comprssion will tend to
close a joint up if it works loose, rather than pulling apart. You can
also make a door with three ledgers so that it has M shaped bracing,
which can look good.
Not much different with power tools, but you'll notice it if you're
So where are your verticals? In a purely ledged & braced door there
aren't any, just the horizontals and the diagonals. The cladding is
merely a cladding, not part of the joinery. Without the diagonal
braces it would of course be a non-rigid parallelogram, which is why
the form with diagonals is actually easier to make. Otherwise you have
to do something with the vertical cladding that's both rigid, and
capable of handling moisture expansion.
I wouldn't use mortice & tenon joints at all. For a more complex door
(shed or garage rather than garden wall) I would do this with a
rectangular frame. Then I would mortice and tenon the uprights and
horizontals, but probably still lay the diagonals on from
"inside" (under the cladding) with half-laps. I'd make them two-thirds
of the outer frame's thickness, so that's half-laps on the diagonals
and one-third on the main members.
There's a lot of experiment needed there, to know how much oversize is
right to drive in securely, but without risk of splitting.
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