Great Outdoors and In have created this page to help to inform potential customers/clients who are currently seeking to have their Domestic or Commercial roof cleaned.
Our other Soft Wash Roof Cleaning page details the soft washing process used to apply a fungicidal wash onto a roof. This page explains how some contractors use an Industrial grade bleach to carry out the cleaning,
We condemn this practice due to the breaches in basic 'site' health and safety regulations and the risks involved in applying the chemical at height.
In the last year some UK Roof Cleaning companies have now adopted the Soft Wash system used in the states in its entirety, which frankly is a process fraught with danger for not only the operator, the owner of the property and nearby neighbors!
As opposed to using a fungicidal wash to carry out the cleaning these companies rely on an Industrial strength bleach as the key ingredient. The product is known in the cleaning trade as 'Hypo' - Sodium Hypochlorite.
Roof cleaning contractors are simply brushing large moss deposits from the roof before spraying the Industrial grade bleach onto the tiles. Some companies apply the 'Hypo' from ground level using modified spray tips to 'fire' this chemical up the tiles! You should never spray up a roof as there is a danger of water penetrating under the tiles and causing leaks!
Other contractors apply the 'Hypo' from the roof ridge, this reduces the risk of 'Hypo' penetrating under the tiles but creates other issues, How does the operator work safety on the roof ? The operators can not use rope access equipment for safety i.e. ropes, harness and grabs as the chemical can attack these!
In either of these methods, there is a real danger of spray drift! This chemical can cause burns and skin irritation, hence why the operator has to wear full PPE (Protective clothing, eye protection etc.) With the 'old' standard Pressure washing method drain pipes are disconnected to stop debris blocking the drains (Note - We don't as we recycle the water) with this method however, the contractor can not disconnect the drain pipes as the chemical Hypo will bleach anything it touches, hence the bleach has to run into the guttering/drains along with any other remaining debris potentially causing blockages!
It should also be noted that this chemical 'Hypo' can attack metal and discolour it, any exposed lead flashing or valleys will be damaged. It is unclear what effect the 'Hypo' will have on GRP valleys, felt trays or even felt runoffs, into guttering systems. Any conservatories below the roofs are also vunerable to damage especially if they have self cleaning glass, as manufacturers only recommend light cleaning and certainly not bleach!
If the operator does not check the conditon of the felt in your loft prior to the roof cleaning process you may get a leak into the loft space, if this happens whilst cleaning using Hypo, you will have bleach dripping into your loft area!
If a roof cleaning contractor advises Soft washing enquire about the chemical being used and please don't be fooled, several companies now add scent maskers to disguise the smell of the bleach.
I have yet to meet a commercial client that would allow Sodium Hypochlorite to be applied to a roof, due to the risk to Health and Safety, So why is it acceptable to use this product on a domestic house roof?