Basement cables, ducts, and pipes.

Cables, Ducts and Pipes. Dos and Don'ts. It is actually very simple. The outside of a cable, pipe or duct are easily waterproofed as they penetrate reinforced concrete. The inside of a duct is extremely hard and could be very expensive to waterproof inside around cables and so on. The flange in this photo is made with Denso tape, a cloth soaked with grease that the gas network uses to wrap round its pipes in the ground.   I saw these expensive solutions at the Build (Bau) exhibition in Munich. I have seen others as well. The lesson has to be Don't use a duct, Or route the duct so water could not get through.   This is a link to a British supplier You cannot reliably waterproof inside a duct for a reasonable cost. One solution someone came up with. After the excess is cut off, it would seem simple to spray expanding foam inside to stop a draught or cold bridge. August 2024. Researching a solution for another issue, I came across expanding mastics. One brand is Swellseal. This links to another here. I cannot endorse them because I have not tried them. Others may be available. Also, be mindful, if they rely upon water to swell, if water is intermittent they could all leak slightly before they activate. I have no idea whether they shrink again when they dry. You need to do more research.

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