If you are planning on undertaking construction work to your property, and in particular removing a chimney breast, you will need to consider how the remaining chimney stack is going to be supported.
The chimney stack is situated above the roof level and is the structure which allows the smoke formed by the chimney to be released from the property.
Generally speaking there are two different ways in which a chimney stack can be supported.
We are now going to look at these in a little bit more detail so that you are fully abreast of them and can ensure that you understand the overall impact that a chimney breast removal will have both on your owner property and on the party wall, with which the chimney breast will be tied into.
Steel Beams
The first form of support to the removed chimney breast comes by way of beams.
The beams or RSJs as they are commonly known within the construction industry will be installed so that they run parallel to the party wall, or wall to which the chimney breast is being removed.
The beams will have to gain support from the walls that run off the flank wall, or party wall and will effectively enable the parallel beam to pick up the load of the chimney breast itself.
The insertion of beams across the party wall or flank wall to offer support to the remaining chimney breast or chimney stack tends to be the more expensive option than that of a gallows bracket.
This is both in terms of its material, however also a result of the structural engineering input and design that will be required in order to accommodate the planned insertion and installation of the steel beam.
However, if indeed you have a party wall, and your neighbour has removed their chimney breast with support by way of a gallows bracket their side of the party wall.
Then you would need to utilise this form of support, as Building Control are unlikely to sign off a gallows bracket your side of the party wall given that there will be significant pressure points to the underside of the chimney stack.
Gallows Brackets
The second form of chimney breast support or chimney stack support is the insertion of a gallows bracket.
Gallows brackets are a relatively straight forward and off the shelf solution, and in many cases can be installed without the need for any form of structural engineering input or design.
The majority of contractor retail outlets will stock gallows brackets and these can be ordered in a variety of sizes, each different size having different structural loads.
Generally speaking, contractors will tend to over-order in terms of the support that the gallows bracket allows for, thereby ensuring that there is no risk of failure to the brackets themselves.
Conventionally above the gallows brackets the contractor will then install a concrete lintel, often reinforced with metal.
This effectively acts as a shelf for the chimney stack or chimney breast that remains in-situ offering a sound and proper support.
If you were to compare the two on a cost perspective, it goes without saying that the gallows bracket option is going to be a lot more cost effective to install. This cost effectiveness comes by way of the cost of the material itself, however also not having to rely upon a structural engineer’s input and design.
Both of these options will fall within the realm of the Party Wall etc. Act 1996. This Act dealing with works that take directly to a party wall.
The Act will set out that Party Wall Notices will need to be served on the owner with whom you share a party wall and with whom the chimney breast is being removed from.
If indeed your neighbour opts to dissent to the Party Wall Notice that you will serve upon them for the removal of the chimney breast, at that stage, you will require the input of party wall surveyors to administer the Act and ultimately agree a Party Wall Award governing the planned chimney breast removal works.
As with the cost of the works, the building owner will need to bear the reasonable fees of the party wall surveyor. The logic here being that it would be reasonable for an adjoining owner to have to pay for professional fees for works that they don’t gain the benefit of.
It is therefore important for building owners who are planning these works to be fully abreast of the potential costs that can come by way of party wall surveying procedures.
Here at Stokemont we are building surveyors by trade, however specialise in party wall surveying.
If you would like to discuss your chimney breast removal works with us, or perhaps discuss your party wall surveying requirements with our team of experienced and qualified party wall surveyors.
Please feel free to give us a call today, or perhaps pop us an email, our surveyors are on call and waiting to assist and advise you.
