In this week’s party wall surveying blogpost, we are going to be discussing party wall foundations and in particular, hit and miss sectional bays.
Hit and miss sectional bays are a form of construction whereby the contractor will dig the proposed foundations in a piecemeal fashion. The piecemeal fashion ensures that the foundation trench is not left open at one time, which could cause slippage to the adjoining owner’s property or structure, or any neighbouring properties and structures, as a result of the open trench being unsupported potentially causing issues and damage.
The process of excavation is a relatively simple one, it starts with the width and length of the hit and miss bays being agreed, commonly this will be in one metre stretches meaning that at any given time the contractor can only have a one metre standalone stretch of the excavations dug and open. This is not to mean that they cannot have multiple open bays dug, it just means that the bays cannot be alongside one another.
Once the bay has been dug, it will then be filled, usually within 12 hours, with concrete or should that not take place, it would be fully supported with shoring thereby fulling supporting the open trench. A one metre stretch of ground would then be left before a further one metre trench is dug.
This type of excavation is preferred, whereby foundations are in close proximity to neighbouring structures, and overall ensures that the risk of damage is as low as it can possibly be.
Contractors will generally be against this form of construction as it is a slower and more complex formation on site, which ultimately means they spend longer doing it.
It is therefore important to ensure that you fully take this into account when designing the proposed works and discussing those with the contractor. The last thing you want to find is the contractor raring to go, and potentially having another site to go to, and then to find out he needs to undertake sectional hit and miss bays, which could significantly reduce the chances of him making the other site appointment and potentially lead to issue with regard to your contract.
If you are planning on undertaking excavation works and believe sectional hit and miss bays may be applicable, give our team of experienced party wall surveyors a call now and we will be happy to assist you.
If you are an adjoining owner and believe that your neighbour should be excavating with hit and miss bays, why not give our team of experienced and qualified party wall surveyors a call now and we will be more than happy to discuss this with you.
