Ron has suggested the correct approach. Timely communication with those who might be affected is generally the key to trying to avoid complaints (although some might complain whatever). Clearly there is a job to be done and there is in practice little that you can do to mitigate the actual noise levels, so the answer is to manage the risk by communication, the times of operation etc. I wouldn't bother measuring the noise as I am not convinced that it will serve any purpose. In the unlikely event that an EHO does turn up I very much doubt that they will take any action unless the timing/duration of the work is unreasonable (in the middle of the night). As A Kurdziael has observed, whether or not this might amount to a statutory nuisance is largely subjective based on a number of factors, including normal ambient noise levels, the time of the day, the duration of the work, the purpose of the work (is the noise unavoidable) etc etc. And I would suggest that by the time that an EHO even starts the process for statutory nuisance, your work is likely to have long been completed. Forget measuring; inform, communicate and get on with the job. You may still get complaints but I would suggest that they are unlikely to result in enforcement action unless the timing, duration etc is unreasonable.