[Pj]

I have been asked to quote a commercial job, quite big new windows, close to the sea, large viewing gallery type.  The construction manager has worried the owners by saying that pure water is corrosive and may damage the sealant mastic.  I don't think it will as long as it has set hard.

What do you think experts?

Does pure water adversely affect new glazing mastic, even over a prolonged period?

I need to give a proffessional answer

Thanks

[007 or what]

I was a window fitter for 8 yrs never heard or this b4

[D.Salkeld_Ltd]

PJ,

Do you realy need the work?
If so then carry out some research.
If not then just say you understand thier concern, you don't believe it will cause any problems but at the end of the day if they want to get someone else you understand.  You may be surprised how thier attitude may change

David

[Moderator David@stives]

Pj

I just a suggestion , just get them to phone Ionics , Omnipole , British water council etc

I would say definately no to your answer .

Does rain affect the mastic?  No

[Nathanael Jones]

Dave has a point,.. acid rain is far more corrosive than neutral pure water!
And Mastic is specifically designed to resist water penetration.

[poleman]

Just do a test on some of the windows - easy really & david has made a good point about rain   

[Pj]

Pj



Does rain affect the mastic?  No

Was interested to see what you guys think.  This is exactly the reply I gave them today Dave, thanks.

I don't need the job, but I do want it.  Looks like I got it today.

[Ian_Giles]

Couldn't agree more, pure water isn't corrosive!
And no way will it affect mastic used for glazing windows!!


Ian

[JohnL]

Dry mastic is just that - dry mastic! Water cannot break it down whether rain, tap, or pure.

However if it is not applied properly and is adhering correctly to both window and its surround or even the surround and the brickwork, any water will penetrate and I wonder if your construction manager is worried that a less than perfect job was done on the installation of the windows and water penetration may occur purely because of the volume of water which will be applied by the WFP.

I would be more worried about the manager and the quality of the initial installation than the possibility of the mastic breaking down.