A ? about roof flashing

[journeyman Mick]

Al,
oh, okay we're reading from the same page then. Just waiting on Peter or Bricks to show how a saw cut inserted flashing can be installed so as to result in a totally dry wall.

Mick

[ozwinner]

I didnt think that flashing was so interesting, but look at all these people who are reading this thread...

Al

[silentC]

Mate, I've always been interested in flashing

[bricks]

I dont know how the wall stays dry fellas, i really don't. It's just the way I was taught.
Just wondering if anyone has had time to look at the pages I posted before, if so what do you think about them?

If anyones wondering, im not argueing about it anymore because i dont like it and because i got spanked by the mod, It hurt, I have sensitive skin.

But mick I cant tell you coz i dont know.

Silent pretty much summed it up for me in post #63

[journeyman Mick]

Haven't had time to look at those pages Bricksie, but stay tuned to this space for breaking news on that issue. I won't steal anyone's thunder, just wait and see.

Mick

[bricks]

Just a question,
Does anyone think the amount of water soaked into a brick wall would have anything to do with the amount of time it is in contact with water/ moisture and less to do with the amount of water?

Eg; if you sprayed your wall with water for an hour or two, then scratched the mortar away I dont rekon youd have had it soaked in even 1-5mm of the way through, Even with a pressure nozzle aimed directly at it.
But if you piled relatively dry soil next to your house, within 1 month youd have signs of rising damp? hence why damp coursing goes above the first corse where theoretically water will pool around the house during heavy storms?


We all know bricks arn't water proof but they arn't tissue paper either.

[silentC]

So why have cavity flashings and weep holes etc at all?

[ozwinner]

So why have cavity flashings and weep holes etc at all?

Bricks do leak and more importantly sweat.
But........
I have never seen a weep hole weep, honest, in all 36 years laying bricks, I cant say I have seen one weep.

Ventilation is the key, if you ventilate then the moisture is almost eliminated.

But hey, dont listen to me, Im just a dumb bricklayer.

Al

[silentC]

Yeah well I know 2 fifths of bugger all about it but I'm just guessing they're there for a reason. I have seen weep holes weeping but only in retaining walls. I can't recall seeing one in a double brick wall weeping but I dunno, it's not like you expect it to come out in torrents or anything.

[ozwinner]

Retaining walls are a different beast altogether, as in that the dirt behind them is constantly moist.

Al

[bricks]

I sweat when i work hard and have to take a leak if i drink too much!

[Bleedin Thumb]

Retaining walls are a different beast altogether, as in that the dirt behind them is constantly moist.

Al

I drilled a hole in a brick retaing wall once, in a plant nursery and water shot out about 3 foot. It was no wonder why the wall was starting to fail.

[journeyman Mick]

I drilled a hole in a brick retaing wall once, in a plant nursery and water shot out about 3 foot. It was no wonder why the wall was starting to fail.

You fool! that was the feed for the irrigation system! No wonder all the plants died in that section.

Mick

[Skew ChiDAMN!!]

Did Friday have an early start this week? Or have I done a Rip Van Winkle?

[Deanom]

Fellas, My 2c worth.
Bricks you're wrong, Pawnhead you're right.
A couple of things I would like to point out on a few items I am qualified to speak.

1. Please dont cut past CG of brickwork unless you are absolutely sure that the wall is properly tied to the stud frame and you arent cutting the bed joint where the ties are. Cutting past the CG (centre of gravity) will create a moment in the wall that will have to be corrected by the ties. Why cut past the CG anyway if the silicone performs the function of sealing and will only really be effective just inside the surface of the bed joint. I would suggest that you should limit cuts to 1/3rd depth if you must make them at all.

2. Breaking out bricks in sections as Pawnhead has described is a practice that is acceptable. This practice is often also employed to replace brick courses when brickies (in their infinite wisdom) provide inadequate damp proof courses and lower courses begin to suffer fret as a result of "salt attack". Check google for more explanation.

3. If the renovation turns the exterior wall in to an interior wall, then you have to flash right through the brickwork. If you want to argue that no water will/should be in the wall, ask yourself why did you put weep holes in the wall at ground level to begin with. If you dont know, dont argue.

4. In most cases we are fortunate that good wall constuction, eaves, good ventilation and good climate all contribute to not having noticeable water in our cavities. Make one of these factors bad and the situation can be different. Eg fact, I recently discovered termites in my house and tracked them back to a perpend where the mortar was not complete. A small little hole existed and they walked right on through the wall. In other areas of the house, black ants have found similar ingress points. Another unappreciated fact is that water can be present in the wall without precipitation outside, eg cold night, cold brickwork, warm house, condensation on the bricks in the cavity. Fortunately in our climate this type of condition does not arrise to frequently. Think of Europe where winters are long and there is a very good chance you are running heating 24hrs for months. This type of situation would likely work the weepholes.

5. Roofing companies only provide details that protect their product and are the easiest to apply. They want to popularise their product so they provide the easiest details. Eg company A provides a detail like bricks' describes, company B provides a detail like pawnhead describes. A silly bugger comes a long (although smart enough to know the difference between easy work and hard work) who wants to build an extension, naturally he selects company A. If a problem arises where the water ingress is beyond the extent of the roof, fat chance that the roofing company will come to your aid. He is protected because his product is not leaking.

6. When I read this thread and also become aware of other insufficient trade practices, I scratch my head an wonder where has all the knowledge gone. As technology improves, are we getting dumber? I am still not supprised those mates of Bricks' laughed at the cavity flash.

Cheers,
Dean