The loft, the walls and the floor Part I By Chris Newman June 7th, 2011
The LoftWe want to keep the central loft space for storage. Mineral wool does not perform well when crushed as it is the air that is trapped that acts as the insulation. One option would be to put in extra cross joists to allow a layer of mineral wool between the original joists and then between the extra joists.Another method which I have chosen as a cheaper alternative is to put 100mm of expanded polystyrene between the joists and another 100mm above the joists. These have then been boarded out with the old skirting boards. This will being the U value to 0.16 Wm-2K.
The skirting boards provide a hard surface for storage and spread any load across the polystyrene to stop it being damaged.The rest of the loft will be insulated with mineral wool between and over the joists to around 300mm.As you can see in the photo on the right the wall insulation is being continued through the roof space and into the mineral wool layer in order to form a continuous insulation envelope layer.
Between The Floors
One of the key area to address when installing internal wall insulation on an older property is the floor joists where they penetrate the wall. It is important to minimise the amount of moisture that could condense on the timbers, to remove any moisture that does condense and also to protect the timbers.We are insulating the walls all the way from the top to the bottom of the house including through the floors. We have therefore using a well considered approach that Parity would normally use with our clients projects which involves using lime mortar to wick any condensed water from the timbers.
One of the key area to address when installing internal wall insulation on an older property is the floor joists where they penetrate the wall. It is important to minimise the amount of moisture that could condense on the timbers, to remove any moisture that does condense and also to protect the timbers.We are insulating the walls all the way from the top to the bottom of the house including through the floors. We have therefore using a well considered approach that Parity would normally use with our clients projects which involves using lime mortar to wick any condensed water from the timbers.
Wall Insulation
We’ve also started putting up some of the internal wall insulation. For most of the main building this will comprise 100mm of PIR. Some 50mm and some 25mm will also be used for thermal bridging purposes.The picture on the right is from the ground floor up. The ground floor is 1 and a half bricks thick (~330mm) and the upper floors are 1 brick thick (~220mm). At the junction we are overlapping the insulation i.e. for a the space between the ground and first floors it is 200mm of PIR.On the wall with the chimney there were some joists very close to the wall. These are only holding up the ends of the floorboards. To allow for the insulation to be continued all the way down these are being moved in 100mm and rehung on joist hangers.
We’ve also started putting up some of the internal wall insulation. For most of the main building this will comprise 100mm of PIR. Some 50mm and some 25mm will also be used for thermal bridging purposes.The picture on the right is from the ground floor up. The ground floor is 1 and a half bricks thick (~330mm) and the upper floors are 1 brick thick (~220mm). At the junction we are overlapping the insulation i.e. for a the space between the ground and first floors it is 200mm of PIR.On the wall with the chimney there were some joists very close to the wall. These are only holding up the ends of the floorboards. To allow for the insulation to be continued all the way down these are being moved in 100mm and rehung on joist hangers.
Other developments:
Installing some heavy duty straps between the main alleyway wall and the joists between the first, second and loft, and also along the roof rafters and the wall. This is being done because there has been some historic bowing of the wall and although it is not expected to move further, just to be on the safe side and for piece of mind, whilst the walls have been stripped back its an ideal time to carry out this work.We also carried out some crack stitching to the top walls internally.
Installing some heavy duty straps between the main alleyway wall and the joists between the first, second and loft, and also along the roof rafters and the wall. This is being done because there has been some historic bowing of the wall and although it is not expected to move further, just to be on the safe side and for piece of mind, whilst the walls have been stripped back its an ideal time to carry out this work.We also carried out some crack stitching to the top walls internally.
We’ve started lifting the ground floor floorboards to allow for the following works:
- installation of mineral wool insulation between the joists
- removal of a couple of bricks in the sleeper walls to allow good ventilation under the joists once the insulation in installed
- running a new gas pipe to a relocated gas meter at the front of the house.
Coming up soon – continued insulation installation, PV install, gas meter connection, new boiler and solar thermal panels, starting the electrics again from scratch and the first windows should arrive fairly soon. Also the planning permission is progressing…….its all go.