A ? about roof flashing

[ausdesign]

Thanks Mick, I was enjoying sitting back and watching.
The greatest occurrence with water penetration in that situation is possibly not with electrocution [point taken] but with water marks or salts appearing on the internal wall in the house. <o></o>
From a builders point of view this type of drop gable is a bastard & there is no one method of flashing that will come up with – ‘do it this way & it wont leak’.
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Firstly<o></o>
Very little water penetrates through bricks. It comes in through the perps. – before I get jumped on by a moderator, bricks do get wet & brickies love laying wet bricks. <o></o>
The higher the brick panel above the abutment flashing the greater the likelihood & amount of moisture in the cavity.<o></o>
The strength of the wind plays an important part, more so with raked or recessed key joints.<o></o>
In an external wall the moisture will have more chance of drying because there is air movement in the cavity.<o></o>
In an internal wall the moisture tends to be drawn through the brickwork because of the temp. difference showing up as effervescence [???].<o></o>
A raked joint will let in more moisture than an ironed joint.
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Yeh ok im getting there.<o></o>
How do you stop it – put in a cavity flashing. <o></o>
As Al showed in his diagram, a stepped flashing with weepholes – a series of horizontal flashings stepping down with the pitch of the roof.<o></o>
But won’t the water run over the edge of the flashing like a waterfall & end up in the bottom of the cavity I hear you say. <o></o>

No. We need to get it into context. We’re talking about moisture not water flowing. If there’s water flowing then its more likely to be a flashing at the very top of the cavity or a couple of bricks left out of the wall [only joking Al] or one of those round grills installed on gable ends to vent the roof space.<o></o>
If you’ve got a single leaf garage you’ll be able to see moisture on the inside of the skin if there’s prolonged rain [& it’s wind driven] If you have say a dry area up towards the top & then water coming in lower and running down the wall it could be more than likely caused by the brickie not buttering the end of the brick fully creating a ‘weak’ perpend.
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In the situation where you have a large expanse of wall above the abutment such as with a full second storey, a full length horizontal flashing as you’d have at the bottom with a slab will reduce the brick area feeding moisture to the stepped cavity flashing. Same as you’d have over a window opening.
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What to do –<o></o>
Reduce the area of the face as much as possible with a ‘normal’ flashing up higher.<o></o>
Ask the brickie to be aware of the potential problem so he will give more attention to perp ends, the installation of the flashings, keeping the cavity clear, making sure weep holes are fully open.<o></o>
Iron finish to the joints if possible.<o></o>
I don’t have much faith long term but clear waterproof coatings work.<o></o>
Liquid damp proof added to the mortar for the entire wall.<o></o>
Use an embossed plastic type flashing in the cavity to maintain a better bond rather than a lead or smooth metal tray/s. - to perform, the flashing has to come within a bees of the face of the brick so you are ‘breaking’ the wall. Either way ensure that wall ties are as close as possible to the flashing.

Whether the abutment flashing is stepped or sloped doesn't come into the performance of the cavity flashing.
As lead will disappear & I think bluescope still have an aversion to laps on their material I may be fulfilled in life yet & see more nice & neat sloped flashings looking modern and not as with their counterparts - left over from the 30's
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Ok sock it to me.<o></o>

[Bleedin Thumb]

That's all well and good Peter, but the original issue was how to Retrofit a flashing in that situation.

I'm starting to think that the best way is to demolish the inner top brick skin to the roof line, place weepholes, cavity flashing etc. IE do it as it should have been done in the first place.
And if that was not possible isolate the whole wall from the weather by cladding, which as you suggested earlier may not be in keeping with the style you want... but hey I'd rather have a dry wall than some architectural anomaly in a place you dont often look.

Edit Hey maybe we have just uncovered a new use for the old Faux Brick cladding!

[silentC]

Corrugated colorbond as wall cladding is all the rage down these parts. In fact, the challenge is to use as many different claddings (the architect wankers call them textures) as you can in the one building.

Or make your extension come up to the eave lining, then you have no problem.

[Bleedin Thumb]

Corrugated colorbond as wall cladding is all the rage down these parts. .

Yes I bet Glenn Murcutt doesn't have any of the problems that we have been discussing.

[Deanom]

Fellas,
One more consideration about lead flashing people should know. Apparently runoff from lead flashing will contain lead ions and if you have colorbond gutters or colorbond roofing, the colorbond's life will be shortened. I have this situation on my tiled roof so I painted the lead flashing (the colour of the tiles) to try not to reduce the gutters life.
Info here http://www.bluescopesteel.com.au/go/...hing-materials
Cheers,
Dean

[journeyman Mick]

Dean,
I believe there are malleable aluminium flashings available toovercome the lead/zincalume incompatibility issue.

Mick

[bricks]

<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER- 1px inset; BORDER- 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by Deanom </TD></TR></TBODY></TABLE>

Another unappreciated fact is that water can be present in the wall without precipitation outside,

Cavity flashing wont stop this???
<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER- 1px inset; BORDER- 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by Deanom </TD></TR></TBODY></TABLE>

5. Roofing companies only provide details that protect their product and are the easiest to apply. ..... company A provides a detail like bricks' describes, company B provides a detail like pawnhead describes. ........, fat chance that the roofing company will come to your aid. He is protected because his product is not leaking.

But if I don't do the install as per manufacturers reccomendations I automatically void my warranty.?????
<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER- 1px inset; BORDER- 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by Deanom
Fellas, My 2c worth.
Bricks you're wrong, Pawnhead you're right.

</TD></TR></TBODY></TABLE>
Due to the fact the this topic is so advanced please provide some proof via weblinks etc as to pawnys method being the only method. I have more than proved that my method is accepted at least by some industry leading companies in this country. Your opinion has already been proved wrong in previous posts.

My only concern about retro cavity flashing is removing the bricks and retaining strength in the wall after. I have not said that cavity flashing is not used, not acceptable, or that it is not done as a retro fit option.
I have not found any proof of cavity flashing as the only option for retro fit- which is what we are asking here.

In order to prove me wrong: you need to find evidence that the saw cut method is illegal, not widely used, and not reccomended by some authority on the matter. Only australian sites will do as our climate is unique from the rest of the world and their reg's dont apply here.

[Bleedin Thumb]

In order to prove me wrong: you need to find evidence that the saw cut method is illegal, not widely used, and not recommended by some authority on the matter. Only Australian sites will do as our climate is unique from the rest of the world and their reg's dont apply here.

Bricks I don't want to get into a slanging match with you but no one has to prove that you are wrong because .........you have not proved that you are right.

In all that junk mail that you posted show us where it says that the correct way to protect the (now) internal wall from moisture penetration in a retrofit situation is by chasing a cut into the brickwork and inserting flashing and fix with silicon.

Also show the appropriate building standard clause and drawing that does the same.( Australian of course )

Time to put up or shut up.

BTW I think that pawnhead is probably wrong as well but his system does make more logical sense from reducing water penetration - there still remains the structural integrity problem.

I still advocate that the only safe way in a retrofit is demolish and redo or totally clad.

This thread has probably unearthed a grey area in building codes that needs some serious thought.

[ozwinner]

Only australian sites will do as our climate is unique from the rest of the world and their reg's dont apply here.

Give me 5 minutes and Ill put it up on my site.

Al

[bricks]

http://www.australinsulation-vic.com.au/PDF%20Files/Econodeck%20Install%20Guide.pdf (PDF file takes a while to down load.)

http://www.tufftile.com.au/technical.html ( go to the instalation manual left side of page , 3218 kb's )

http://www.hamiltonroofing.com.au/glossary.htm ( first image of page as it opens)

WWW stramit link broken ?????

http://www.harmonyrooftiles.com.au/m...oreword.html&0 (section 5.3) 5.3.a is the image of what I do exactly.

http://www.bluescopesteel.com.au/ind...F600C04FCF6B8F (PDF) Section 11 at the bottom of the page.

Im not going into a slanging match either.
I've produced pretty good set of reputable suppliers and installer who support saw cut methods in retro fit applications,
I can not find anything on retro fit cavity flashing for australia, any where at all, If anyone else can please post them here- I am genuinly interested.

IMO both exist, cavity flashing retro fitting requires that you remove bricks, saw cut does not, for that reason if you are going to choose between the two, then choose saw cut if you can.
That is my position and has always been my position.

[Bleedin Thumb]

Bricks just posting the same old links is not proving anything. I said before if you are going to provide a kink at least have the courtesy of linking to the correct page. The only reference you provided was section 5.3 of Harmony roof tiles site. Have you actual read that section. It has no relevance to what you are expounding on what so ever in fact the mentioning of stepped flashing supports Pawnhead not you.
I said last post its time too put up or shut up. I don't think you are capable of either.

[bricks]

Section 5.3 shows exactly what i do, if pawny does the same thing then we are acheiving nothing here, and we've been doing this for nothing.

I have amended the links page to show exactly where you need to navigate to find pictures or diagrams of what I do.

[Groggy]

I read an article today on how the USA does it (in a Reader's Digest Home Improvements Manual). It shows a new (shingled) roof being fitted to an existing wall and describes the process as:

• fit step flashing
• fit shingles up to wall
• cap flashing is applied over the step flashing and the lip is laid into a slot cut into the brickwork (or mortar joints if the flashing is level). The lip/brick joint is sealed with sealant.

[ozwinner]

I still cant believe that flashing of the waterproof kind can produce such an interest in people..??

Al

[Groggy]

100 posts in this thread Al, maybe we're missing something here?