Changing the internal layout of a property can be one of the best ways of transforming its appeal without spending a fortune. Taking out internal walls to open up the living space can be very tempting, especially in smaller dwellings, for example ‘knocking through’ front and rear reception rooms. But in some cases this can be structurally unwise.
In period properties there’s a danger of creating a sterile environment devoid of the historic features and original layouts that many buyers demand, thereby reducing
its market value. Also, internal partitions can perform a useful function keeping conflicting activities in the home separated.
But as long as they’re carefully planned, layout alterations can be highly successful at overcoming drawbacks with the original design. For example, houses with a
warren of small, dark rooms can benefit enormously from the improved light gained by opening-up. Or in properties with small kitchens, taking out the wall separating the kitchen and
adjoining dining room can dramatically improve the layout at minimal cost compared to building a new extension.
Removing internal walls
Some internal walls are fundamental to the structure of the house. Some offer fire protection to the stairway, and others simply divide up the space within the house
and are relatively straightforward to alter or remove.
Load-bearing walls obviously require very careful consideration before they can be altered or removed – work which requires Building Regulations consent. In most
cases you will need to consult a structural engineer to design a suitable beam or some other supporting structure so the loads are safely transmitted to the ground. Before demolishing an internal wall there are two key questions to ask:
Is it load-bearing?
It’s not always obvious which walls are holding things up, and which are merely partition walls. But if you get this wrong, you’re in serious trouble. In most properties, especially older buildings, the internal walls will normally be supporting
roof loadings, floor joists or walls upstairs. In some new properties that are constructed using ‘timber frame’ techniques inadvertent removal of walls can also cause structural problems.
Does it protect you from fire?
Walls around staircases offer protection allowing you to escape in the event of a house fire. Altering these will require Building Regulations consent, even if they’re not load-bearing.
Similarly, partition walls that separate entrance halls from reception rooms are best left intact, since they form a readymade fire escape corridor to comply with Building Regulations should you want to convert the loft. These walls are particularly important in houses with three or more storeys. If they are removed it’s essential that mains-operated smoke detectors are fitted and that windows to upstairs rooms are suitable for fire escape purposes. If you wish to remove such a wall, contact us and we will be happy to advise whether they are essential to fire protection and whether any additional work is needed.
How can you tell if an internal wall is ‘structural’?
It’s a bit of a myth that if you tap a wall and it sounds hollow it’s just a studwork dividing wall. In fact, some stud walls are loadbearing. Conversely, solid masonry internal walls aren’t always ‘structural’ – some were built as simple partition walls. To see if an internal wall is load bearing, check if it’s supporting:
In older houses the roof structure often relies on support from an internal wall. More modern roofs with ‘W’ shaped roof trusses (introduced in the late 1960s) are designed to span right across the house from one main wall to another without internal support.
Floor joists rarely span more than about four metres without support from an internal wall or beam. Look for nail runs in floorboards to see the direction of joists (at right angles to direction of floor boards).
Loadings from walls above
Ground floor walls often extend upstairs as bedroom walls. However, sometimes upstairs walls are offset or supported on a beam. Most modern houses have lightweight stud walls to the upper floors.
In older houses, internal walls often provide ‘lateral support’ helping to tie together the adjoining walls either side.
If in doubt the best advice is to consult a structural engineer or building surveyor, but in most cases a Building Regulations application will need to be made.
Before making any sort of structural alteration to your home a Building Regulations application must be made. Building Control will then inspect the work on site as it progresses and ultimately issue a completion certificate.
As well as ‘knocking through’ internal walls there are several other types of popular structural alteration, such as the removal of chimney breasts to free up living space, and enlarging openings in main walls to provide bi-fold garden doors.
If such works are carried out illegally without consent, it can cause major problems when you come to sell or re-mortgage – as well as being potentially dangerous. So it’s reassuring that Building Control will be conducting site visits to check the work and offer professional advice.
To safely make a structural alteration you obviously need to provide an alternative means of support to the loadings above. A structural engineer will need to calculate loadings and design a suitable solution. For example, where chimney breasts are removed, the remaining masonry above (to the chimney stack via the loft/ upstairs room) will still be taking loadings from the chimney stack and will need to be supported. This normally requires the insertion of a suitable steel beam fully supported at either end on padstones.
Similarly, where load-bearing internal walls are taken out, a steel beam will normally need to be inserted to transfer the load to the side or party walls. Where party walls are not strong enough to support such extra loadings, new brick piers or steel columns will need to be installed to support the new beam, which could mean having to excavate small foundations internally, adding to the expense and disruption.
Making an opening
When making structural alterations, temporary support must be provided before any demolition is carried out. For example, when taking out a wall, the masonry above must be supported while a slot is cut for the new lintel. This is done by first cutting holes just above the position of the new lintel through which sturdy timber ‘needles’ are placed. These are supported on either side by adjustable steel ‘Acrow’ props which should rest on a scaffold plank to spread the load.
New lintels should normally extend either side of the proposed opening by at least 150mm bearing. To spread the load, additional support will be needed under the ends of the lintel, such as a padstone or a hard engineering bricks. Once safely supported, the new opening can be cut out underneath.