What are weep holes on new build houses?

We explain what weep vents are on new builds and why they are often fake!

So you may have heard about weep 'holes' or weep 'vents' in new build properties and you may have even been warned about fake or dummy ones. Here we'll explain what their purpose is, why there are fake ones and how we identify those that aren't real...

What weep holes are:

With cavity wall construction you will have at various 'openings' on the external fabric (brick or render typically) something called a cavity tray. These are installed above windows, doors and even meter boxes on your home. 
The external fabric of your property is not meant to be impermeable (water resistant) so in heavy rain there is the chance for it to pass through the brick / render or through the mortar, and get inside the 'cavity'. The cavity of your new build house is a gap between the outer fabric (brick / render) and inner blockwork / timer. The reason why new build houses have a cavity is partly to allow for insulation to be put inside to keep the house warm in winter and cooler in the summer. 
So, where these openings such as doors and windows occur in your house,  there will be something called a cavity tray. The purpose of this is to collect any rainwater that manages to find its way into the cavity. Then to allow for the rainwater to easily exit rather than pool on the cavity tray, there will be weep holes.
Weep vents come in a few different shapes and sizes, ranging from a long thin type as shown above, or most commonly they will be a quite small circular piece of plastic. 
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Why are there fake weep holes?:

The answer to this is simple and it is because often the bricklayer forgets to install them and so rather than retrospectively fixing them in properly, they chop them in half and glue them in place.
The issue is often worse than this because on occasion they haven't just not installed the weep holes, they often do not have a cavity tray at all.

How to identify dummy weep holes:

We spot-check if dummy weep vents have been fitted by tugging slightly on several weep vents around the property using small pliers. They should not come out easily, but typically the best giveaway is if there is no visual sign of a cavity tray.