Building Projects - Two Storey Extension
An in depth diary of a two storey extension on the back of a Victorian house.
From demolision of the old extension through to completion of the project we show you what it's really like to have a team of profesional builders in, and how each stage of the building work gets done.
With all the paperwork from planning approval to signed agreement of the quote, work gets underway on this two storey extension starting with salvaging the old kitchen, arrival of a skip and a quick chat about security on site while the works are carried out
Demolition starts on the extension but it’s all very methodical with the plasterboard ceiling and walls stripped first before stripping back the flat roof and removing the boards and joists.
The bricks on the new extension need to match the house. Salvaging or reclaiming any bricks they can, the builders take down the old walls. The remaining bricks and rubble will be used as hardcore for the oversite concrete slab forming the floor.
A hydraulic breaker is used to break up the old over site concrete forming the base of the old extension, followed by the paved area and path which aren’t as deep and a low level garden brick wall. Care has to be taken around the water main which runs beneath.
Our team of professional building contractors sets out and excavates the foundations for the new extension. Excavating most of the depth with a mini digger and barrowing the soil to a skip, the final work is done by hand. A drain run passing through will need to be bridged.
Despite limited access to the site, ready mixed concrete is used for the strip foundations. The builders talk to the neighbours so everyone is kept happy and in no time the concreting is finished and the site left clean and tidy
Lines are set out for the two skins of the cavity wall and the foundation levels are made up ready for the first few courses. With stepped brick corners built first, the remaining brick and block work is brought up to damp proof course.
The hardcore sub base of the ground floor slab is compacted and blinded with a layer of sand before a damp proof membrane and thermal insulation are laid on top. The concrete slab itself is poured in two stages allowing for the steel mesh reinforcement to be included
The cavity wall is constructed with an outer leaf of reclaimed bricks, cavity insulation, and an inner skin of blockwork. Stepped leads are built first, ensuring that they are level and vertical. A builders line is then used to guide the full courses and the brick work is pointed as the work proceeds
Scaffold has been erected allowing the next lift of brick walls to be constructed ready for the steel work on which the smaller footprint second storey will sit.
Cutting out the chimney breast will maximise space in the room. Acro props with strongboys are used to support the brick work above while the chimney is removed. A new steel is hoisted into position spanning between the front and back walls and finally packed in place with slates.
The back wall of the house is propped up and new steel work installed so that the old back wall can be taken out producing one large room. Additional steels to support the second storey of the extension are hoisted into position and the various sections bolted together with custom made steel plates.
Two sets of joists are fitted between the steels at first floor level. The top set for the floor to the upper room is fixed on joist hangers. The lower set for the ceiling below are notched and wedged on the flange of the steels.
The cavity walls are built up from the steel work to form the upstairs room of the extension. The brick work has been carefully blended with reclaimed stocks to match the original house and includes two red brick dentil courses.
A new window opening in the solid brick side wall of the original house is cut out ready for the arrival of the new window frame, and a new doorway allowing access to the under stairs cupboard is cut through from the front room.
The roof of the extension comprises three sloping elevations and is cut in to the old roof. With the new ridge and hip timbers in place, the main rafters are installed followed by the infill rafters and the timbers forming the new valley section. Plastic fascias and soffits are installed and the new roof frame is ready for covering.
The large steel sections previously installed are battened out and covered in two layers of plasterboard to provide suitable fire protection as well as a flat decorative surface. With the steels encased they are now ready for skimming when the rest of the walls and ceiling get plastered later.
The new section of roof is covered with a roofing membrane and tile battens, then reclaimed slates are laid and nailed in place. The valley is lined with lead and slates are cut in here as well as along the hip. Angled clay tiles are bedded in mortar along the ridge and hips to finish off the new roof.
The small first floor roof sections to the rear and side of the extension are framed out in timber. Insulation is then installed before laying a roof membrane and battens on top of which the slates are fixed. The slates are cut round a soil pipe and new roof light, and a lead flashing is fixed along the junction between the roof and the walls of the house.
The plasterers prepare the walls and ceilings with pva and use bonding to make up the low areas before dry lining some of the walls. Plasterboard is fixed to the new ceiling and the bare brickwork has two coats of sand and cement. The walls and ceilings are then all finished with two coats of finish plaster which is polished up to leave a smooth flat surface.
New window and door frames are installed. Cavity closers with an inbuilt dpc are fitted to the cavity wall openings in the new brick work. New openings are knocked through the solid brick side wall of the original house. The frames are lifted into position, aligned and secured with frame fixings before being sealed with expanding foam.
The cabinets for the new kitchen have been custom made and arrive pre assembled, They are set out, aligned, adjusted using the screw up legs and fixed in position using metal brackets screwed to the wall. Cut outs in the back panels are made with a hole saw to accommodate the services – hot and cold water supplies as well as waste pipes for the sink, dishwasher and washing machine, and a gas supply for the hob.
The new French doors are trimmed before fitting with brass hinges and installing the double glazed units, mortise lock and handles. Vertical sliding sashes are fitted to the new window frames – one with fixed side lights and corded sash weights mounted in the sash box either side – the others have modern spiral sash balances fitted. Fitch fasteners are installed secure the windows, and rack bolts to secure the doors.
Granite worktops cut to size in the workshop complete with cut outs for the sink and hob have been delivered to site. The granite has rounded corners and hand polished edges. The tops are installed, the joints sealed and a hole cut out for the freestanding tap.
Laying a sand and cement screed over the existing concrete base in the new extension brings the floor up to the required level and matches that of the original part of the room. The semi dry mix is barrowed from the delivery lorry, shovelled out across the floor, levelled with a steel straight edge and smoothed with a plastic float.
The plasterboard ceilings and stud walls are skimmed with two coats of finish plaster. The brick and block walls are sealed with pva before applying two coats of hardwall plaster which is left scratched up before skimming with two coats of finish plaster and polishing up with a steel trowel to leave a perfect smooth surface.
A new soakaway is built using modular attenuated cells covered in a permeable fabric and set in a hole beneath the lawn. Rainwater will flow to the soak away via a new plastic drain from the back of the house and will disperse gradually into the surrounding soil.
Review of the completed two storey extension project looking at how extras are dealt with as well as valuations and payments and, how the final snagging list is drawn up and the job signed off by the Client