Supporting the Ceiling in a Loft Conversion
Changing Your Existing Ceiling JoistsYou will find when you start your loft conversion that your current ceiling joists in your loft will not be adequate to support the weight of your loft conversion. A ceiling joist is the big bit of wood that holds up your floorboards, so it is important that it is strong enough to take the weight. Generally ceiling joists that support the flooring in a loft are not designed to hold a lot of weight. So, in order for your loft to have adequate support, you or your builder will need to put in new larger ceiling joists next to the existing joists.
Your new joists will need to support the existing purlins and struts in your ceiling; your structural engineer should be able to advise you which work will need to be done.
Your Existing RoofYour existing roof will be made up of number of timber structures which will make up the overall pitch. A typical loft roof will include a ridge board, which will form to create the point of the roof and what the rafters will be attached to. You will also have struts and purlins on the roof which will also help hold the weight of the roof.
If your builder removes any of these then it could alter the stability of your loft so it is important that you speak to your structural engineer about any changes they will be making to your loft. When designing your loft conversion your architect should consider what impact any removal of these will have on the structural work of the loft. It is important that not only the ceiling under the flooring of the loft is stable but also the roof itself.
Your loft roof will not have had to cope with the demands that will be placed on it once it has been converted. It will need to make sure that it is insulated and able to keep in the heat and the rain and wind out. If nobody has lived in the loft before you may have to revamp the roof to accommodate for this.
Removing The RaftersIf you plan to install a skylight or a window in your loft conversion you will need to cut an opening in the existing roof rafters. You may need to install new timbers in order to support the gap that has been made in the rafters. Your dormer extension may support the gap, but you will normally have to put new rafters on top of the existing ones to give the extra support to the window and the rafters that are missing.
You shouldn’t need to worry too much about the structural work of your loft roof and ceiling as this should be the job of your structural engineer, but you should consider the disruption that this may cause to the rest of the house. Your roof will need to be cut open at some point, and the builders may need to adjust the existing framework, so be prepared for a lot of disruption to your house.