Chapter 2: Existing structure
When thinking about adding a loft extension, you do need to bear in mind the basic structure of your house and whether any walls or even the foundations may need strengthening to support the new addition, particularly where current load bearing walls have any openings.
Load Bearing Walls
A load bearing wall is basically any wall which keeps your house upright by taking the weight of it, from the roof to the foundation. The weight being transferred down at any point in the house is called the ‘load’ which is where it gets its name from.
You can’t just knock down load bearing walls or add a great deal more weight to them without potentially causing problems to the overall structure of your house, so when adding the additional weight of a loft conversion, existing load bearing walls may need to have extra support included to support the new load.
Just because a wall has openings – doors, archways, kitchen hatches – or has been knocked through to make a larger room, it can’t be assumed that it isn’t a load bearing wall. Some houses have also been built with a through lounge as one of the original features, done by having a steel or timber beam or lintel installed over the opening to support the weight.
Your contractor will check what, if any, changes, need to be made for any through rooms or walls with openings to support the weight that will be added by your loft conversion.
Usually, adding a loft conversion won’t add a huge extra load on your existing foundations so there won’t be any need to reinforce them, however the condition of the current foundations should be checked by a qualified engineer for things like subsidence, drains, trees very close to the house, any other building works which might affect the house foundations and damage since the house was built to make sure work can go ahead.
Depending on what you are doing, the increase in load could be so much that the foundations will need to be reinforced with underpinning.
Your contractor will be able to give you advice on what needs to be done.
Questions about the existing structure of your house? Need to speak with a contractor? Call our experts at County Lofts on 0800 046 1995.