|
|
 |
The
Ecohome : Second floor bedroom
A very old carpet, polystyrene ceiling tiles, paint and wallpaper
were the surface coverings in this room. The ceiling sloped toward
the eaves as it does now but stopped some 1200mm (4') in front of
the eaves so that the room was narrower. A stud wall separated the
room from the roof void behind. The original cast-iron fireplace
was painted white.
The walls, ceilings and floor were cleared as in the landing, and
the skirtings, architraves and door were taken away to be stripped.
The strategy was then to simultaneously extend
the room into the roof void and to build the roof sub-structure
ready to accommodate high levels of insulation. The plaster on the
stud wall and ceiling was hacked off and the timber lathes were
pulled off taking care not to damage the rafters. The vertical rafters
or 'studs' which formed the structure of the removed wall were actually
found to be forming a kind of hybrid structure, transferring some
of the loading from the roof onto the floor and vice-versa. Their
removal would result in both an understuctured floor and roof. To
deal with this, the purlin running along the top edge of the line
of studs was strengthened with a steel plate. The floor, already
'bendy', was dealt with later. The studs were removed and the former
roof space opened up.
As the insulation required was of loose construction,
a rigid structure was built up which would allow the insulation
to be blown in. Because of the existing structure, this method is
inherently more time consuming and therefore expensive than building
from scratch - but it does use fewer materials. Sheets of 9mm Scandinavian
Birch plywood were cut into 300mm wide strips which were then fixed
to the side of each rafter. To the bottom edge of each plywood 'web'
was fastened a 50mm (2") square softwood batten which formed
the lower flange of the new 'beam' structure. To the top edge of
each 'beam' - just below the tiling battens - a 25mm (1") square
batten was added to each side, forming an air gap for ventilation.
These battens were then underclad with 15mm Bitvent rigid breather
board cut to fit between the rafters. The underside of the completed
structure was clad with a thin polyethylene vapour barrier followed
by ordinary plaster board. The first choice here would have been
Claytec boards as used in the bathrooms, primarily to increase the
thermal mass, but for reasons of cost the plasterboard was used
as a compromise.
A skylight was installed, this time top-hung,
to introduce more light, ventilation and drama to the room. A silver-backed
blackout blind in white was added for extra night time insulation.
The external roof
covering was overhauled from above. The slates were carefully removed
as were the tiling battens. A new layer - breathing felt - was then
introduced and new battens laid. The slates were then reused where
possible (some do break on removal) and these were supplemented
by closely matching reclaimed slates.
Before the plastering, the loose cellulose
insulation was installed by a specialist contractor. The procedure
involved the material being delivered compressed in bags, which
was then fed into a special machine which loosens the fibres and
blows it under pressure through a long flexible pipe into the required
area. While most of the insulation was blown in from above, accessed
through the roof hatch, the area at the rear close to the eaves
was accessed differently. Because of the purlin supporting the roof,
the insulation was not able to fill the space from above, so 75mm
(3") holes were drilled between each of the joists and the
insulation blown in from here. The holes were then re-sealed and
can still be seen in the airing cupboard behind the hot water cylinder.
The slope and the vertical received 300mm (1') while the flat received
400mm.
The floor needed to be strengthened to make
it less flexible. The floorboards had to be taken up for this -
another time consuming but necessary job. Once they were all removed,
steel plates were bolted to the sides of the floor joists. The opportunity
was taken to insulate the floors for sound - particularly useful
in a house with mixed occupancy. For this, loose-fill Rockwool insulation
was used, followed by a 5mm layer of Regupol. This is a sheet sound-insulating
material made of cork and recycled rubber. The floor boards were
then replaced, sanded, coated and waxed as in the landing. As the
floor area was extended, extra boards were needed which were taken
from the floor in the room adjacent. Extra reclaimed boards were
purchased and used in the next room.
The plastering was then progressed, with
lime used on the walls and Tierrafino on the ceiling in Delphi White,
trowelled for a smooth finish.
The walls were then painted with Nutshell casein
paint and Ochre Red natural pigment in the ratio of one kilogram
to one sachet.
Finally, the woodwork was refixed and the
original fireplace stripped back.
The sound insulation has had the effect of also acting as thermal
insulation. This has meant that despite the external wall insulation
not being in place the room is virtually surrounded by a thick blanket
this room warms up very quickly when occupied and only requires
minimal heating on very cold days - the theory is proved even before
completion!
Continue
the tour >>
|
