How to build a
A deck consists of a very substantial sub-frame
that you don't see, covered in the decking boards that you do see.
The sub-frame is built to the same standards as in
the upstairs floor of your house. It should be very solid to the point
that you don't realize at all that you are walking on a structure
above the ground.
- Framework of 150mm x 50mm (6" x 2")
at 500mm (19") centres
- Ground supports at maximum of 1.5m ( 5ft)
centers, i.e. no more than this span between supports.
- This gives a main frame where there are spaces
no more than 1500mm x 500mm, these spaces edged
by 150mm x 50mm (6" x 2") timber
- These spaces should be filled in cross-ways using
at least 100mm x 50mm (4" x 2") giving a
maximum gap size of 500mm x 500mm (19" x 19")
- All cut ends of decking boards and tannalised
timber should be treated with timber preservative
(not cheap "fence coat")
- Area under the deck should be stripped of
turf and weeds and have a landscaping membrane laid
with gravel over the top to keep it in place and prevent
Reversible Treated Deck Board Smooth/Grooved
2.4m Deck Board each £5.98
3.6m Deck Board each £8.58
4.8m Deck Board each £13.48
Pack Of 20 Deck Board 2.4m £107.60
Pack Of 20 Deck Board 3.6m £169.60
Pack Of 20 Deck Board 4.8m £206.60
Pack of 120 Deck Board 3.6m £895.38
144mm wide and 28 mm thick Deck Boards for you to cut
To build a deck from scratch you'll need a firm base.
Decking Joist Green Treated 2.4m each
Decking Joists Pack Of 20 3.6m - £365.88
Green treated decking joists 144mm wide and 44mm
thick, use to build a firm base for your deck.
Decking Kit Packs:
3.6m x 2.4m £407.98
4.8m x 2.4m £501.98
3.6m x 3.6m £509.28
4.8m x 3.6m £622.68
Treated Reversible Deck Boards: Thickness - 28mm, Treated
Decking Joists: Thickness - 44mm, Width - 144mm, To build a deck from
scratch you'll need a firm base. High quality Finnforest Deck Boards
& joists will give you a quality deck that has been manufactured to
last, 15 year manufacturer's guarantee against rot and insect attack
Build Deck Kit Green Treated 2.05m x 2.1m -
If you're looking for a high quality deck but don't
have the time or skills, then look no further than this ingenious interlocking
deck kit, The timbers are machined so that they slot together and interlock.
Decking Screws 4.0 x 65mm Pack of 100
Timbadeck Decking Screws 4.0 x 75mm Pack of 100
Timbadeck Decking Screws 4.0 x 85mm Pack of 100
Timbadeck Decking Screws Bucket 4.0 x 65mm Pack of 1300
Coated high grade steel for extended
life. Sharp point, sharp thread and reduced shank allow easy driving
without splitting wood. For timber decking and other external timber
applications. Prodrive recess. Bugle head. It is recommended to use
stainless steel decking screws with pilot holes when installing hardwood
Deck-Tite Screw Bucket 8ga x 2" (4.5 x 63mm) Pack of 1000
Drill / Drivers
Titan TTD272DDH 14.4V Ni-Cd Drill Driver
Erbauer ERD182DDH 14V Drill Driver £84.99
Makita 6281DWPE3 14.4V Cordless Drill Driver
Direct Power DPB212CSW 185mm Circular Saw 230V
Erbauer PSC1585L 185mm Circular Saw 230V
Sparky TK 65 185mm Circular Saw 240V
Prices for guidance only, correct at time of writing,
subject to change
Plan of a 3.1m x 3.1m
(10ft x 10ft) deck.
2" (150mm x 50mm) timber main frame
at maximum of 500mm (19") centres.
Minimum 4" x 2" (100mm
x 50mm) infill timber frame. maximum unsupported
area 500mm x 500mm (19" x 19"). The gaps are shown
for clarity - there shouldn't really be any gap!
Ground supports at
maximum of 1.5m (5ft) centres.
These sizes are the limits of what should
be used, if the deck is 4m x 4m for instance, an extra set
of ground supports should be used, rather than "stretching
it", likewise extra infill should be used rather than
make the unsupported gaps even larger.
Aim to "over-engineer"
This is timber that has been treated with a long-lasting
preservative. A copper-based stabilizer compound is forced deep
into the timber under pressure. This results in a finished product
that is impregnated with a long lasting preservative far better
than you could ever manage just painting it on. It should be used
for all outdoor woodwork as it will last far longer than untreated
timber or any timber that you treat yourself. It also means that
you don't need to worry about timber that is out of sight and
can't be re-treated.
Tantalization results in timber that looks very
much like it does in the raw state. It is not strongly coloured
having only a slight green tinge to it and can easily be stained
with exterior wood stain that takes almost exactly its intended
- Use a straight edge from which to measure your deck
- usually the house.
- Mark out the outline of the deck to begin with
using builders line.
- Right angles can be fixed using a "framing
square" - a large set square about 16" x 24".
Alternatively three pieces of wood nailed together with
the edges in the ratio 3:4:5 will give a right angle
- measure carefully and make it large, a 1mm error over
1m is less important than over 10cm.
- Dig foundations first for the supports and place
the supports very carefully and accurately.
- Don't rely on the timber you are using to
be as straight as it should be. Exterior grade tannalised
timber and decking boards can be somewhat warped, especially
over the lengths used in deck building. Rely on your
builders line for accuracy, not the pieces of timber.
Deck foundations should be laid on either large
4" x 4" (100mm x 100mm) tannalised posts set into at least
1ft (30cm) of concrete in the ground, or onto breeze blocks laid
flat and bedded onto a dug-in concrete foundation. The first
gives the minimum extra elevation i.e. deck at about 6" (15cm)
above ground level, the second gives extra elevation of the breeze
block too unless these too are dug into the ground (with concrete
Go deeper than 1ft (30cm) for post foundations if
the deck is to be elevated up to 2ft (the same in the ground as
out of it). If the elevation is over 2ft then consult the professionals.
If you don't feel you need to, then you are already beyond the
scope of advice on these web pages (or you should be).
It is possible to secure the edge of the deck to
the house using a "wall plate", I prefer not to do this
if possible so as not to start drilling into the brick work. It
is perfectly possible to install a deck right up to the house suspended
on free standing fixings.
Use large and substantial fixings.
On the main frame use at least
90mm x 6mm screws, three off at each corner joint. Pre-drill
a 4mm hole so as not to split the timber near to the
edge. Alternatively use coach screws 100 mm long into
pre-drilled holes. Coach screws give a protruding head
whereas normal wood screws can be driven flush with
the timber (you may need to counter-sink).
- Decking boards can be held in place with decking
clips, decking screws or nails. Decking screws leave
the most visible head, but are probably the most secure
fixing and also the most time consuming. If using nails
hire a "Paslode" nail gun from your local
tool hire firm, these run on gas and each nail is fired
into the wood by a small explosion. Always fix with
at least two and preferably three fixings at each point
to prevent "dishing" of decking boards as
they weather. Fix decking boards whenever they cross
a frame member.
Your decking boards are what will be seen, so when you come to
placing them take a little extra time to get things right.
- Only join cut decking boards above a frame member
so that the ends of both boards are suspended.
- Use a fine-toothed saw to cut the ends of decking
boards and avoid splitting of the wood, either a
circular off-cut saw or a jigsaw.
- Seal all cut ends of
decking boards with timber preservative.
- Use pieces of 5mm thick wood as spacers when
fixing decking boards against each other, fix the ends
first and then the middles - not all decking boards
are as straight as they should be and this will "iron-out"
- The edges of your deck will have visible rough cut
6" x 2" (150mm x 50mm) timber, face this
with decking boards for a better finish.
- If your deck is not laid at perfect right angles
due to surrounding areas then lay the decking boards
at 45° this covers up a multitude of sins.
Tools and equipment
Measuring tape- min 5m
Builder's Line - pins and nylon
Chalkline, (also useful for lining up screws if using
these to fix decking boards)
Framing square - big set square
for larger measurements
Spirit level - the longer the better.
Saw ( a must, there's a lot of large pieces of timber
to get through)
Drill (optional but hugely useful)
Miter Saw (optional)
Power Augur (optional,
for making post hole - can be hired)