Airtightness of wall penetrations

[WWilts]

New build in progress. Cost considerations

For various reasons, there will be some penetrations of the external walls (100mm, 150mm, small overflow pipe sized etc). 

Thinking of buying some EPDM roofing material and cutting grommets as needed, to maintain airtightness. Is that EPDM suitable? 

[PeterW]

Why ..? Buy the standard products off the shelf that are available …

 

https://www.go-banana.com/products/Lighting-Electrical/Electrical-Accessories/Cable-Accessories/Cable-Glands-Grommets/Pro-Clima-Roflex-Airtight-Pipe-Grommets-6623245.html?variant=Roflex 100