Building a
Summer House
Save over £1000 by building your own summer house. Buying a standard
construction kit and with erection charges would cost you over £2000 for a 2.4m
by 2.4m summer house.
The plans detailed below show how a similar building can be built for
half that figure.
The timber construction uses standard building materials which been
obtained from a local building supplies company. The building proves strong and
warm with a double skin of insulated walls. The size of the summer house selected
is 2.4m x 2.4m and 2.8m high. But these dimensions could easily be adapted if a
different size was required. Most of the construction can be done with one
person and the materials can be purchased in smaller quantities on a just in
time basis so cash flow is maximised.
So let’s get started:-
1. The Site.
The site needs to be level and cleared of plants and debris also you
need a clearance all around the Summer House of not less than 400mm. In this
example the Summer House is 2.4m x2.4m with angled double doors with a small
inbuilt canopy.
The diagram in fig1. shows
the main floor beams: 100mm x100mm x2400mm fencing posts have been used. The
corners are joined by 160mm coach screws. Each corner is supported on concrete
pads which extend about 450mm into the ground. You may have to dig out deeper
if the ground is very soft. See fig 2.
When constructing the base frame lay a 3mx3m
damp proof membrane over the concrete piers. This will stop the timbers rotting
and keep the Summer House free from rising damp. Make sure that the membrane is
positioned equally as this will be extended up the wall for additional
weathering. The centre beam ‘F’ should be attached to the perimeter beam by
using joist hangers.
At this point it is important to note that all screws and nails should
be zinc coated or galvanised so they will not corrode.
With the main frame complete you can now install 100mm x50mm joists
@400mm centres using joist hangers. Make
sure that all the timbers are treated with a wood preservative.
1500mm
2. Wall Frames
Fig 4 shows the rear wall. The construction is from 47mmx47mm sawn
treated wood. The vertical members are equally spaced and fixed using 100mm
x10’s wood screws. The horizontal members are also equally spaced but offset to
allow for ease of screwing. The top timber is 98mmx47mm this wider to allow for
the roof construction supports.
When you have completed this wall frame you need to repeat for the other
wall. This is made in the same way but the length is 2350 to allow for assembly
of the other frame and give an overall size of 2400mm.
3. Wall Frames with Windows
The next two wall sections incorporate the windows. Each window opening
is approx 600mm wide x 1500mm high Fig 6 shows the configuration.
In this example one window wall is slightly wider than the other to
suite the site location. They can be equal in size but you need to plan this
part carefully to ensure that the door opening is in the region of 1200mm if
you require double doors. The top beam needs to be left at 2400mm and trimmed
when fitted. Repeat the construction window wall for the remaining window.
Screw the members together using 100mm screws and ensure that pilot holes are
drilled to avoid splitting of the wood.
With the construction of the four wall sections the can be assembled to
the base frame. This operation is easier with two people but it can be done by
one person but, the use of clamps is essential.
Start with the two large wall sections and butt them together and clamp
to make it easier to screw them together accurately. Fig 7 shows the operation
in plan view.
Pre-drill the vertical members in four places at equal distances and
screw with a100mm
screw. Next screw the low level timber to the base again with 4 x 100mm screws
for each wall section. At this stage the clamps can be released because the two
wall sections will stand up OK on their own.
Next add the two window wall frames. First, by clamping and then screw
with 4 x 100mm screws. At the top floating end of the 97mm x47mm beam screw one
to the other by using a coach screw (100mm) see fig no8.
Check that the overall length of
the top beam is 2400mm and saw off any excess wood. Square up the frames. There
is every chance that the walls are fairly square but at this stage it is
advisable to check the diagonals and then temporary nail timber planks at an
angle to ensure that the frame remains square while the horizontal plank boards
are fitted. Vertical tie bars are recommended to be fitted to the base and
vertical wall frames, one on each elevation should prove sufficient.
4. External Boards
There are two options for the external cladding. We chose to use tongue
and groove floor boards because they were cheaper than external cladding and
thicker hence stronger ie. 18mm thick instead of12mm
for standard external cladding. Boards can be fixed from the bottom up wards
but make sure the tongue is face up to allow any water to drain away from the
timber also use water proof glue in each tongue
and groove joint. Clamps may also be useful to ensure the boards are
tight together. See fig 9
If the wall is exposed to view a
chamfer looks good and helps moisture to drain away from the planks. This can
be achieved by using a hand plane or router.
Repeat this operation until the whole wall is covered with timber
planks. For our summer house it took 19 blanks per side. Secure the planks with
65mm long nails. As mentioned before nails should be galvanised or treated to
prevent corrosion.
When all the boards are fitted ensure that all new timber is treated with
a wood preservative. Repeat the operation for all other walls. Now you will
notice that the structure is very firm. The glued planks effectively form a
solid piece of timber with numerous fixings into the wall frame. Check for
square and remove any temporary diagonal
boards.
5. Roof Construction
The roof is designed to have a slope of 22 degrees and is generally
constructed from 75mm x 47mm timber. It is made up of an ‘A’ frame and other members are attached to this through a multi-
layered central column. The photo shows the completed assembly.
The top apex is fixed with a nail plate at ‘A’ see fig 10
.
The ceiling truss is screwed to the roof truss at point ‘B’ and trimmed
to the profile of the roof trusses see fig 11 below
At ‘C’ (see figure 10) the vertical 97mmx47mm timber is fixed to the
ceiling truss with 100mm screw s but a cut out is formed for another truss
which is installed in the opposite direction. See fig 12 below.
Now two additional lengths of 97mm x47mm are fixed either side of the
vertical roof truss. See fig 13
Joist hangers should also be used to strengthen the joints. At this
stage you can erect the truss in position and fix to the wall frame with 100mm
screws. The other joists which run at right angle to the main ‘A’ frame are now
fixed and the over-hang at the fascia board of 250mm is maintained.
The horizontal ceiling joists are now fitted and blocked up at each end
by 75mm pieces of timber. Note: This joist is not for fixing the ceiling but
acts as a secondary support for other ceiling joists. See fig. No 14
The roof structure in plan view should look like fig 15.
The additional members must be profiled so they fit squarely on to the
vertical central column. To make this task easier the angles can be set up by
making a template of card board and then this can be transposed on to the wood
so the angle cut is right first time. The overhang of the corner trusses is
greater than the previous truss because they are not at right angles to the
wall i.e. this should be 353mm instead of 250mm.
To complete the roof structure 8 smaller trusses need to be fitted in
between the trusses to form a grid of trusses at approximately 600mm centres
fig16 shows the completed layout.
At this stage it is important to check that all the ends of the trusses
line up so that the 100mmx18mm fascia boards can be fitted. These can be
screwed or nailed into the end of the trusses.
It’s a good idea now to fit the top boards above the wall plates to the
underside of the roof boards. See fig 17
6. Fixing the Roof Boards
For best results the roof shingles need to lay
on roof boarding. Sawn gravel boards are suitable for this 150mm wide x18mm
thick x 2400mm or 1800mm long can be used. Fig 18 shows the layout of one
segment.
Each board is cut at approx
45degrees at the ends at allow the next segment of the roof to butt up neatly.
More than one board is required for the perimeter edges so make sure they are
cut so the joins line up with the centre of the roof trusses.
7. Windows and Doors
To simplify some of the work standard doors were used for the main doors
2x 550 x1960 doors were used these required an internal frame size of 1175mm
wide x1960mm high . The door frame was made from 75mm x47mm timber and screwed
to the adjacent wall frames. Angled pieces of wood were fitted between the
vertical members to ensure a snug fit. Short supporting timbers were fitted to
the horizontal top door frame to the roof section to tie the structure together
for maximum rigidity. See photo below
The windows were made up from a further set of double doors but cut down
to 500mm x1500mm. One window was top hung and open able the other was fixed.
Standard locks, handles and window stays were fitted as for normal doors and
windows.
Corner Cover Strips
To cover up the ends of the wall planks and the fixing nails 50mmx18mm
timber is used and bevelled with a router and pinned into position. Similarly
around the windows the cover strips are mitred.
Adjacent to the door the cover strips are 75mm wide and grooved to take
the ends of the adjacent wall planks. See fig 19
Weather Proofing
the Roof.
The roof is proofed with bitumen shingles these are nailed and mastic
sealed to the roof boards. Make sure you pick a dry and warm day to carry out
this job so that mastic adheres well to the felt and the shingles mould easily
to the roof.
The photo below shows the roofing process.
The shingles are laid starting at the lower edge of the roof and worked
up to the peak. At the peak the felt is dressed to the vertical column. A
square capping box is
fitted over to finish off. Also a vane could be fitted her to give the building
an elegant look.
8. Internal Walls and
Ceilings
If you plan to have electrical lights and power in the summer house now
is the time to do the first fix of cables. Also for maximum comfort fit 50mm
insulation panels in the walls and roof.
The walls can be clad with a light weight cladding system
100mmx9mmx2100mm. Start at one side and pin through the tongue and grove to
avoid having too many nails showing. Make sure that each strip of cladding is
tight to the other as the wood will shrink as it dries out. The use of a nail
gun will simplify this job.
When the walls are complete the same principle can be applied to the
ceiling. It is advisable to form a small access panel in the ceiling for future
access to wiring etc. and inspection. The power sockets and light fittings can
be fixed and tested.
9. Flooring
The floor joists have been designed to fit standard tongue and grooved
boards. Start at one side and butt the grooved side of the board to the wall.
Nail through the tongue if you don’t want to see the fixings.
Make sure each board is tightly fixed to the next board otherwise large
gaps will appear when the boards shrink and dry out.
9. Painting the Summer House.
Outside should be treated with a paint which allows the wood to breath
and hence additional coats can be added in the future without paint flaking
off. If the wood has not been previously treated then it is suggested that 3
coats should be applied. Use contrasting colours to bring out the features of
the summer house.
Internally a simple clear
vanish to the wood or sealant to allow the natural beauty of the pine wood to
look it’s best.
10. Landscaping
around the Summer House
You need to some thought to the surrounding areas. Gravel or paving
slabs can be laid and gives a good finish to show off the best of your Summer
House.
Your project is now finished and we hope you have many hours of enjoyment
using it.