ventilation brick big no no?

[chris day]

Hello guys

A client has requested I replace wiring carried out recently by a builder which consists of an SWA running from the DB, under the floor which then runs through the ventilation brick, the cable had then been run across the garden bed to the flood light mounted on the post.
I would like the dig a 600mm trench which will involve extending the cable as the floor has been laid inside the house, am i over thinking this by suggesting the cable passing through the vent brick is quite bad?

 

[LankyWill]

The ventilation bricks are there to ventilate the foundation space beneath your home. Some properties have large amounts of a radioactive substance called Radon, that is why the vents are they to allow the gas not to build up and become dangerous.

Id suggest just popping a 25mm hole through the adajecent side of the brick vent and threading the armoured through there instead. Why they did that in the first place is beyond me!

 

[Octopus]

If you are "replacing the cable" why can't you dig a deeper hole?

 

[Grant webber]

I always thought air bricks were installed to prevent air being damp and stagnent and rotting the timber joists. Could be wrong. Why u would run a cable through them i dont know. I dont really see how it would be a big no no though. Just not the smartest thing to do

 

[PEG]

Standard "air bricks",fitted to conventional cavity wall properties,are there to ventilate the sub-floor area,which in older,conventional timber floor construction,assists in preventing timber issues. In non-sleeved cavities,they can cross ventilate cavity areas,or ventilate solid insulated floors,with the damp/gas membrane,lapped above.

They would not be used to ventilate Radon gas,as this is usually "capped" to the periphery of a property,to prevent direct ingress,via floor areas.

There is a common theme,with certain trades in this country,whereby a lack of understanding of the function of standard building practices,leads to poor long-term thought,when undertaking additional work on a property.

 

[Specialist]

There's possibly a Rule / Reg somewhere that covers it but I honestly can't remember, doesn't really matter.
To me it's just sheer laziness & bad practice, would agree with Lanky & Murdoch: New hole & Deeper trench.

 

[LankyWill]

Standard "air bricks",fitted to conventional cavity wall properties,are there to ventilate the sub-floor area,which in older,conventional timber floor construction,assists in preventing timber issues. In non-sleeved cavities,they can cross ventilate cavity areas,or ventilate solid insulated floors,with the damp/gas membrane,lapped above.

They would not be used to ventilate Radon gas,as this is usually "capped" to the periphery of a property,to prevent direct ingress,via floor areas.

There is a common theme,with certain trades in this country,whereby a lack of understanding of the function of standard building practices,leads to poor long-term thought,when undertaking additional work on a property.

i think you should read this-https://www.bre.co.uk/filelibrary/radon/56998_jRadonSht2PP.pdf

 

[Specialist]

So basically your both right, air bricks can be used to help vent Low levels of Radon. When higher levels are present then ducted ventilation is used to vent the radon to atmosphere.
Years ago we were taught that vent bricks were there to provide cross ventilation of underfloor spaces, this was to help stop dampness & rotting floor timbers.
In those days things like Radon & the problems it causes weren't so well understood or publicised.

 

[PEG]

i think you should read this-https://www.bre.co.uk/filelibrary/radon/56998_jRadonSht2PP.pdf

I have,14 years ago,when it was current. The "further information" and the "disclaimer" at the bottom of the missive is an indication of what was coming...

Very similar processes occurred during our building industries exploration of other issues in folly,such as insulated concrete floors,cavity insulation,wall ties and many other decade-long experiments.

It is not ignorant or arrogant,to remember that a great deal of our building control specifications,are minimum standards,and not best practice or top-drawer

 

[Pat H]

Ventilation bricks provide ventilation. That's their job.
Using one to pass a cable through will reduce the available ventilation ability of that brick. It will however save having to punch a hole through the fabric of the building that could otherwise be avoided.
I wouldn't alter a run to use a vent brick as a route but if the vent brick was in the right place and there was plenty of ventilation then why not save drilling an extra hole through the brickwork.

 

[sparkdog]

I've seen a few cables run through ventilation bricks by Bodger Bills. I would never do it myself its really naff.