The tasks to identity a low-rise domestic building and outline the key external features. The domestic property I have chosen for this project is 3 bedroom end of terrace house located in Wandsworth Greater London. The building is timber frame with a strip foundation and a pre-fabricated timber panel roof; it is one of 24 built on a small housing estate in the late 1960’s.
1.3 Key External Features
I have taken 3 photographs of the building showing the key external features.
* External Walls
1.31 South Elevation
Eaves Guttering Soil Vent Pipe (SVP)
1.32 West Elevation (Gable End)
Half round ridge tile
Stretcher Bond Brickwork
1.33 North Elevation
Windows on external wall Flashings
1.34 External Walls
The facing of the external walls on the house is stretcher bond brickwork. The advantage of stretcher bonding is that the wall acts as a whole so that a load of a beam carried by the topmost brick is spread to the two bricks below it, then to the three below that and so on down to the base or foundation course of bricks.
* 1.32 North Elevation there is a damp-proof course (DPC) which acts as a barrier to the upwards passage of moisture or water between the parts separated by the DPC. There is a requirement in the Building Regulations that a cavity should be carried down to at lease 150mm below the level of the lowest DPC.
* On the front and rear of the house 1.31 & 1.33 Elevations the house has vertical tiles hung which double lap on timber battens nailed to counter battens.
The roof is a pre-fabricated timber panel roof.
I have a found a modem method for a timber panel roof, it is called a smart roof its works as an interlocking panel system.
The panel connection system using tiles and battens as traditional construction as you can see below.
This allows for maximum economy in site labour as it requires a less carpenters to construct.
The rafters are fabricated from light section, stress graded timber, which are accurately cut to shape, assembled and joined with galvanised steel connector plates.
The eaves on the house are for the lowest courses of tiles and the timber supporting them. Much of the preparation for the panels is off site which results in the minimum of site labour.
As you can see from 1.31 South Elevation and 1.32 West Elevation:
* There is a ridge vent which is designed to release moisture from the roof to stop the build up of condensation.
* Soil vent pipe (SVP) is for the venting of foul water drains which is
necessary to prevent a concentration of gases and retain the air inside the drain at atmospheric pressure. It is a direct connection with the discharge stack and drain to the public sewer provides a simple means of ventilation through every stack.
1.36 The Eaves
The eaves are closed and protected by soffit boards which are painted white for aesthetics and the protection of the timber. There is also a fascia boards which is nailed to the rafters and ceiling joists. This is so the fascia board covers the cut ends of rafters and projects 25 to 30 mm above the top of rafters to act as bearing for the lowest courses of tiles which project discharge rainwater into a gutter fixed to the fascia/gutter board.
fascia boards fascia boards
Soffit boards to eaves soffit boards
There are a variety of different windows on the house the front (1.31 South Elevation) is made up of:
* side hung casement
* horizontally pivoted
* 3 x top hung sash
The (1.33 North Elevation) is made up of:
* 2 x horizontally pivoted
All the window are made of wood which is the traditional material used for windows, most of the windows are still the original from when the house was built with the exception of the top left on the 1.31 south elevation and the garden doors on the north side.
The advantage of a pivoted opening of a casement is that the weight of the frame and glass is balanced over the pivots that are fixed centrally.
A side hung basement consists of a square or rectangular window frame of wood with the opening casement hinged at one side of the frame which allows it to open out.
The window is a top hung sash, used for ventilation; it opens outwards so that the slope of the sash and its glass directs rain outside the building.
The lintel is a Catnic that is used for timber frame construction it is single element lintel with a sloping outer face and Duplex corrosion protection which together provide a built in DPC.
The window has a wooden frame and which is painted white for protection and aesthetics, the window seal is a red clay tile that is sloped to allow rain water to run off the seal.
The house has guttering on it north and south elevations known as half round eaves gutters it has a stop end outlet which connect to the down pipe on both elevations. The guttering is made out of plastic which is robust, durable and has a long life span.
The guttering allows the smooth running of water away from the building and stops the potential dangers of leakage, dampness and overall penetration of water through the external wall and roof.
The drainage is a separate system, the vent pipe allows for the foul drainage to be vented preventing smells coming into the house, the foul runs out of the house along a manhole into a separate drain while the rainwater is collected in the guttering and runs down the around a foot this is formed centrally under load-bearing walls. This continuous strip
1.5 Sketch showing load bearing walls & 1.8 scale drawing of foundations.
The house should be built on a strip foundation which consists of a continuous strip steel reinforced concrete, to a depth of serves as a level base on which the wall is built and is of such a width as is necessary to spread the load on the foundations to a area of sub-soil capable of supporting the load with out undue compaction.
1.9 Hot Water System
The hot water system is indirect. The water comes from the main’s, the pipe branches off leading to the kitchen coldwater tap, for drinkable water the other pipe leads to the cold water storage tank in the loft.
Where the mains water enters the house there is a combined stop and return valve, so all the water supply can be stopped, drained away to stop back siphonage.
The cold water storage tank has a ball valve within it to control the depth of the water and also an overflow pipe which leads out of the south facing soffit boards incase the ball valve corrodes and malfunctions.
The pipes entering and exiting the water storage tank have servicing valves. Water is fed into the top of the tank and it exits at the bottom of the tank to enable circulation of the water.
The water is gravity fed through the pipes to the water storage cylinder. An electrical water pump is fitted to aid the gravity feed.
Pump Flow and Return pipe
Cold water storage cistern
Expansion and feed cistern
The water storage cylinder, as pictured above houses the water in its outer vessel whilst the inner coil of hot, segregated water heats, the water. Once the water is heated it exits the tank via the top where it is then connected to the hot water pipes for the kitchen sink, toilet sink (upstairs and down) and the Bath.
There is a pipe running from the top of the water storage cylinder called the vent pipe in case overheating of the water within the cylinder occurs.
1.91 Heating System
The heating water system is an indirect heating system, which is from the same condensing boiler as the hot water heating system.
The water comes from the mains and is branched off in a separate pipe for the heating system, which leads up to the loft, into a smaller heating water storage tank. The tank is equipped with a ball valve, over flow pipe and lid.
The water is fed down to the boiler, where the water is heated within the pipes by ignition of gas, this water is then feeds in a circular formation to the water storage and radiators cylinder. The water is kept separately from the hot water by the segregation of the 2 systems.
Water Storage Cylinder
Ventilation pipe Hot water fed to tap
Hot water to radiators
Coil filled with heating water
Hot water from boiler
Cold water piped in
Entering at the bottom, the opposite side from the water, also heating the water on the outside of the coil, for the hot water taps.
The boiler is a Potterton Promax HE Plus (SL) range gas fired room sealed fan assisted condensing central heating boiler.
The boiler is suitable for fully pumped open vented central heating and domestic hot water systems. It is a high efficiency boiler with an automatic ignition.
Flow and return pipes
Flue elbow Condense waste pipe
Gas supply pipe
The boiler has a wireless system which consists of a digital programmable Thermostat and a wireless time switch to control the water and heating.
Time Controls Temperature Control
Pipes run through the radiators allowing the water to enter and exit the radiators, on opposite sides, whilst a secondary pipe runs the course of the radiators reheating the hot water and circulating the cold.
Temperature Regulator Radiator
The heating water storage tank is rarely used as the water circulates around the system. If the radiators need to be changed or fully bled then it is easy to refill them. The tank also has a vent pipe over the top of it incase the boiler overheats or there is a problem with the water storage cylinder.