vertical dpc

[vibetime]

hi all, i need to know if vertical dpcs are really needed for adding conservatories to the back of my house, it will have two walls of full height glass pannels and one will be a cavity wall, i dont like the idea of cutting through the outer skin as it must weaken the wall , and if the cony was to be removed it would leave a unsightly line.
but then again i dont want damp problems ?

 

[vibetime]

anyone !?

 

[The-brickie]

To be honest if your looking a doing a proper job, then you would need to put in cavity trays too.. I'd say if your not that exposed, no driving rain then dont worry to much about it

 

[vibetime]

thanks for replying
i wont bother with cavity trays as should be ok, but it worrys me about cutting through the outer skin, it must weaken it , and my house was thrown up (persimmon) so would be dubious on amonut of wall ties !
are there any alternatives to cutting a dpc in ?

 

[The-brickie]

I wouldnt worry about a vertical damp, if your going to get damp it will be from above unless theres a lot of driving rain hitting your cavity wall, please dont go down the route of covering the brickwork with a 'weather seal' type solution, it doesnt work, the rain gets in thru cracks and bad pointing

I used to cut in vertical dpc's, even up the back of the frames but like you, I like the idea that it can be removed (the conny) without too much damage to the house so I dont cut them in any more and touch wood, I've had no troubles.

So no, not really any other alternatives that I can think of.

 

[^woody^]

If the wall where the frame will abut does not get a load of driven rain, then you can do without a vDPC

Otherwise coat approx 300mm of the existing exterior wall adjacent to the frame with a silicone water repellent (Thompsons or similar)

Or, if the internal wall is to be plastered, then apply a 300mm strip of waterproofer (Superprufe or similar) adjacent to the frame before plastering

I am surprised that you are worried about a vDPC but not bothering with cavity trays. Water penetration from the wall above the roof is more of a problem than moisture tracking sideways around the frame

 

[The-brickie]

Thats me and ^woody^ agreeing on it! (apart from the waterseal) we used to argue about the colour of the sky

So there you are, dont fret to much unless the back of your house is subject to the full force of the weather.

 

[vibetime]

cheers guys for your help

 

[^woody^]

The sky is not blue, that's for sure