The guidance from the Health and Safety Executive advises that, where portable lavatories are in use, you should have 1 unit per 7 staff members working 40 hours per week. However, in the case of demolition sites, it also states that staff must have access to running water, seating, and consumables. Therefore, in these cases, welfare or shower units should also be supplied. You have a duty of care and a legal responsibility to ensure there are adequate facilities on-site, and we have plenty available to help you keep your site compliant.