Weep Vents

[Thermo]

and seeing as you like to go by manufacturers instructions and recomendations have a read here joe!

http://www.timloc.co.uk/Technical_support/Cavity_trays_technical_data/Stepped/default.aspx?id=79

 

[joe-90]

We've been living in houses in this land since before Christ walked the Earth. That's 2000 years without weep vents. Are you seriously suggesting that we've had water running down our inside walls for 2000+ years and nobody knew how to fix it?

 

[Thermo]

no but they werent building cavity walls 2000 years ago! (and im not saying that single skin are necessarily bad!) but there is your answer as to why they have weep holes and what they are for.

 

[joe-90]

We've had cavity walls since the thirties - why has no-one noticed in all those years that cavity walls allow rain in? And why do cavity walls allow rain in when single skin houses don't?

 

[Thermo]

actually they were around at the beginning of the last century.

enough said i feel, night night

 

[Shytalkz]

We've had cavity walls since the thirties - why has no-one noticed in all those years that cavity walls allow rain in? And why do cavity walls allow rain in when single skin houses don't?

And, in the old days, we didn't have insulation in the cavity either, but we do now .

Prior to the manufacture of proprietary weepholes, perps over openings were raked out. This suggests that there were indeed recorded instances where damp transferred across the cavities in the vicinity of openings and that the weepholes were then introduced as means to prevent this.

 

[hotrod]

As with a lot of things BRegs-wise, it's a sledgehammer to crack a nut and largely superfluous in many instances - exposed areas subject to driven rain would be an exception. But, regardless of its efficacy or even its necessity, the reason for its inclusion is as per Nose's comments.

I think Shytalkz has hit the nail on the head with his comments here. I don’t think anyone is suggesting that cavity trays and weepholes are a necessity in normal circumstances per se. They are required by the Building Regs, so we fit them, simple. I would be very surprised if there was any evidence to suggest that the internal skin of a cavity wall had prematurely 'failed' due to penetrating damp purely through the omission of cavity trays / weepholes.

I'm no environmental scientist, but I imagine it would require exceptional metrological circumstances in which moisture transfer is possible across the external skin. The moisture would then have to either:-

i) Vaporise and travel across the cavity before reaching the internal skin and carrying on its merry way (or more likely, imho, just 'drip' down the cavity)
or
ii) Use whatever cavity bridge is in situ to complete the moisture transfer process across the cavity.

I can understand the logical theory behind weepholes, but in all honesty I think the benefit is so negligible to not even be worthy of consideration with regard to wind driven rain in the majority of UK locations.

Weephole (definition) - hole through a wall that drains water to its outer face.

 

[joe-90]

We've had cavity walls since the thirties - why has no-one noticed in all those years that cavity walls allow rain in? And why do cavity walls allow rain in when single skin houses don't?

And, in the old days, we didn't have insulation in the cavity either, but we do now .

Prior to the manufacture of proprietary weepholes, perps over openings were raked out. This suggests that there were indeed recorded instances where damp transferred across the cavities in the vicinity of openings and that the weepholes were then introduced as means to prevent this.

As an engineer you should know that a wall will not transmit moisture to the point that it will run down the inside of a wall rather than run down the outside of a wall. If you don't understand that you aint no real engineer. It's basic physics.

The only time you get water on the inside of a cavity is when the roof has seen better days and the roofing felt rots back so that instead of discharging into the gutter it discharges down the cavity. If you are a REAL structural engineer you will be familiar with this occurrence. I'm beginning to have my doubts that you are. A single skinned, well pointed wall will not transmit driven rain into the house - let alone run down the walls. Every terrace house with header bricks would allow moisture ingress if what you claim is true. But it's not true is it? You are a bluffer.

 

[Shytalkz]

Don't start on me just because you've been shot down in flames by just about everyone on this thread, you narcissic onanist.

I made no comment as to their effectiveness, or even need; I merely pointed out the reason as to why they were introduced. And it had nothing to do with the bleeding roof!

Talking of which, felt was not present on early roofs btw, or are you aware of ye olde Tudor roofing feltte? With an adequate lap on the tiles and pitch on the roof, there would not be any requirement for felt and its use these days is primarily to allow the roof to breathe, not to stop rainwater getting in - and certainly not into the cavity - which is closed, uh duh.

As it happens, moisture can track across the cavity: mortar snots, misaligned wall ties ring any bells? Or would you deny that that has ever occurred, as well?

 

[Deluks]

Joe - You are the weakest link, good bye!

We had some pretty harsh rain not too long ago, along with some very strong winds. I was standing in my kitchen and I felt water splashing onto me. Looked down and sure enough a small puddle had formed on the window sill. Further investigation (by which I mean, looking up a bit) revealed that water was coming through just above the window, being forced through the wall by the wind pressure. The upvc frame is sealed and the soldier course pointing is intact. To my knowledge this has never happened before and hasn't happened since. I can also say the same for the weather that day.

So I have witnessed first hand that in rare freak occurrences, a 'good' wall will ingress water.

 

[noseall]

[As an engineer you should know that a wall will not transmit moisture to the point that it will run down the inside of a wall rather than run down the outside of a wall. If you don't understand that you aint no real engineer. It's basic physics.

.

you DO get water droplets forming on the inside of a wall, in adverse weather conditions.

normally a porous brick wall gets soaked then it dries. in adverse conditions i.e. driving rain, the wall gets a continual soaking until it becomes saturated.

it is after saturation point that when a drop of rain falls on the outside of the brick it forms a droplet or bead of water on the inside. this carries on until it actually starts running down the inside.

now for the love of god stop making a fool of yourself and quit digging holes.

 

[Shytalkz]

now for the love of god stop making a fool of yourself and quit digging holes.

Poor deluded Nose...just like the mods, Joe is never wrong.

I've been temporarily banned from the info forum btw

 

[joe-90]

Joe - You are the weakest link, good bye!

We had some pretty harsh rain not too long ago, along with some very strong winds. I was standing in my kitchen and I felt water splashing onto me. Looked down and sure enough a small puddle had formed on the window sill. Further investigation (by which I mean, looking up a bit) revealed that water was coming through just above the window, being forced through the wall by the wind pressure. The upvc frame is sealed and the soldier course pointing is intact. To my knowledge this has never happened before and hasn't happened since. I can also say the same for the weather that day.

So I have witnessed first hand that in rare freak occurrences, a 'good' wall will ingress water.

You need new windows.

 

[joe-90]

[As an engineer you should know that a wall will not transmit moisture to the point that it will run down the inside of a wall rather than run down the outside of a wall. If you don't understand that you aint no real engineer. It's basic physics.

.

you DO get water droplets forming on the inside of a wall, in adverse weather conditions.

normally a porous brick wall gets soaked then it dries. in adverse conditions i.e. driving rain, the wall gets a continual soaking until it becomes saturated.

it is after saturation point that when a drop of rain falls on the outside of the brick it forms a droplet or bead of water on the inside. this carrie

s on until it actually starts running down the inside.

now for the love of god stop making a fool of yourself and quit digging holes.

One of the basic laws of physics is that water (or electricity) will always take the easiest route to earth. In a saturated brick that easiest route is down the outside of the brick. Try it yourself. Get a hose on a brick wall and stand there for a few days - you won't get water running down the far side. Go on - prove physics wrong if you can. Then tell me why it doesn't happen on header bricks. (I take it you know what a header is?).

 

[joe-90]

now for the love of god stop making a fool of yourself and quit digging holes.

Poor deluded Nose...just like the mods, Joe is never wrong.

I've been temporarily banned from the info forum btw

If I'm wrong - then so is physics. Tell me why header bricks aren't prone to leaking through into the house. I take it you know what a header is?