Need to add airbrick channel under solid concrete extension - HELP!!! Read more: https://www.diyno

Discussion in 'Job Talk' started by dee-b, Mar 27, 2018.

  1. dee-b

    dee-b New Member

    Hi All,

    I have just bought an old 2 story singleskin (no cavity) mid-terraced house that has suspended wooden floors throughout.

    Ive been hacking away at the ungodly amount of renovations that need doing and come across one that has me stumped...

    A more recent extension has been built running the full width of the house at the rear and it has a concrete base. It seems that this was built by a real cowboy and is the cause of alot of pain for me atm!

    I have pulled up the floorboards to the rear of the living room (where it joins the extension) and can see that the joists/noggins and boards all look OK (no signs of damp etc). However upon inspection I can see that the 2 original airbricks that were in the rear of the living room have been knocked out and one of them seems to have copper pipes running into the extension (radiator I assume) and nothing else and the other 1 has a length of pvc pipe (about 6 inches) running under the concrete floor and out to the rear airbrick.

    I have checked the rear airbricks that were fitted on the extension and confirmed that the one with the copper pipes seems to be completely blocked (unsure as to why they would have fitted it in the new extension wall and not laid a pvc channel under the floor, and the other has most of the holes blocked besides the middle few that line up with the diameter of the pvc pipe (thank god it runs all the way!!).

    So my questions are:
    - Am I right to panic here? given there is no damp under the floor is it safe to assume the current ventilation is adequate? or is this a disaster waiting to happen?

    My initial thoughts to remedy this (if needed) are:
    - Kango out 1 or 2 channels in the extension floor, hopefully missing pipes and lay new channels.
    - Kango out a small area near the living room wall and retrofit some ground vents so air can transfer into the extension rather than under it.
    - Rip out the old airbrick with the pipe behind and fit some sort of pipe --> brick adapter (if needed)?

    If I need to address this i'd rather go for 2nd option (less kangoing/concrete/mess) however I assume the original airbrick holes are below the DPM that is under the extension floor (will try and confirm tomorrow). If this is the case I assume there is no way I can breach the DPM with the kango, fit the vent and then somehow fix the DPM?
    could I line the entire void under the vent with DPM to ensure any moisture couldn't penetrate into the concrete floor above the DPM?

    Please send over any thoughts/ideas!


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