Cavity trays in external wall insulation?

[TimL]

Hi everyone,

 

We're adding ~300mm external wall insulation and render to our 70s terraced house (looking to achieve EnerPHit, hence the especially thick EWI), and we're trying to find some information on cavity trays and weepholes.

 

What we know:

1. In at least one instance, we have a sloped lintel which acts as our cavity tray.
2. There are no noticeable existing weepholes above any of the openings.
3. Based on the "Weepholes" section of https://nhbc-standards.co.uk/6-superstructure-excluding-roofs/6-11-render/6-11-7-detailing/, we think that we don't need weepholes since we are in a moderate exposure zone (Stockport).

 

Our questions are:

1. If we have interpreted the above guidance correctly, would that mean it doesn't matter if our cavity tray doesn't have stop ends (we believe these may be missing)?
2. Similarly, considering the questionable build quality, we're not certain if the meter boxes or if all the other openings in the external wall are fitted with cavity trays. Would cavity trays even be needed if we are installing EWI and render? 

 

Would appreciate some advice on the above, or if anyone has done similar work please tell us how you did it! 

 

Thanks all