Gap to leave between bottom tile and shower tray?

[cyradsyv]

Hi,
Could someone tell me the best size gap to leave between the bottom tile and shower tray for sealant? My tiles are 8mm thick and I'm going to use Dow Corning 785 sealant.
Thanks very much.

 

[foxhole]

No gap you just increase risk of leaks by leaving gap, you seal the tray to the wall , tile down to tray and seal again between tile and tray giving a double seal against the water.

 

[Richard C]

You should have a small 2mm gap to allow for expansion. I silicone in 2 stages; leave the nozzle uncut & inject between the bottom of the tile & tray & scrape off any excess flush, cut the nozzle to the appropriate size & run a second bead between the face of tile & the top of the tray, smooth off & job done; none of my showers leak.

 

[cyradsyv]

Thanks for the reply foxhole.
I've been using 2mm spacers for the wall tiles, but I thought that wouldn't be enough to leave between the bottom tile and the shower tray in case of movement or some other reason, so thought I might have to leave more like a 5mm gap or so. You think 2mm gap will be ok then?

 

[Richard C]

Snap

 

[cyradsyv]

Hah...timings everything.

I'll go with the 2 mm gap then.
Should the final smoothed off seal then run from the bottom edge of the tile to the shower tray at a slight angle or straight down vertical?
And should the sealant slightly overlap the bottom of the tile or start right at the edge?
Just like to get it right!

 

[Richard C]

Cut the nozzle at an angle to give a radiused silicone bead that will just overlap the tile face; getting the bead the right size & looking good is a matter of technique & experience. Heres a quote from a recent thread; I never use plastic smoothing gizmos but they can be usefull if you can't get it right.

cut the nozzle at an angle to the desired bead width & pull the gun at the same angle, don’t push it; the trick is to apply the bead in one fast, continuous action using moderate pressure on the trigger. With practice you will get a nice even bead every time. The mistake practically everyone makes is to apply the bead too slowly; a natural thing to do but it usually has the opposite to the desired effect. All you have to do to finish it off is spit on your finger & run it along the bead; or if you don’t like the taste of silicone, use a drop of watered down Fairy Liquid as Woody suggests.

 

[cyradsyv]

Super, appreciate the info, it's a great help.
Cheers..

 

[jefoss]

i use fugi occasionaly for sealant pretty good actually

 

[gcol]

You should have a small 2mm gap to allow for expansion. I silicone in 2 stages; leave the nozzle uncut & inject between the bottom of the tile & tray & scrape off any excess flush, cut the nozzle to the appropriate size & run a second bead between the face of tile & the top of the tray, smooth off & job done; none of my showers leak.

You wanna run me through that again?

 

[Goldberg]

No gap you just increase risk of leaks by leaving gap, you seal the tray to the wall , tile down to tray and seal again between tile and tray giving a double seal against the water.

How do you seal "between tile and tray" if you left "no gap"?

 

[Richard C]

You should have a small 2mm gap to allow for expansion. I silicone in 2 stages; leave the nozzle uncut & inject between the bottom of the tile & tray & scrape off any excess flush, cut the nozzle to the appropriate size & run a second bead between the face of tile & the top of the tray, smooth off & job done; none of my showers leak.

You wanna run me through that again?

Which bit your not gonna give me grief as well are you, it's bad enough coping with joe

 

[big-all]

i always leave 5mm so if you get any shrinkage and the tray drops say 1 or 2mm its easier for a 5mm bead to stretch to 6mm than a 2mm bead to stretch to 3

 

[Goldberg]

If the tray drops 1-2mm then there's something wrong with the floor.

 

[jefoss]

If the tray drops 1-2mm then there's something wrong with the floor.

not normally, the trays do move a tad, especially when some heffa gets on it.
always best the leave a 6 foot gap and silicone it.