View Full Version : how to 'ground' a gelcoat tub's flimsy quality? also, vikrell question.

12-12-2004, 07:27 AM
greetings all!

i'm choosing fixtures for a bathroom, and i'm on a slim expense account.

i'm looking at soaking tubs, in both gelcoat and acrylic - just for soaking, not for whirlpool use.

would prefer an acrylic tub, but might not want to spend the extra cash on this item. (cast iron is a favorite, but not in my realm at this time)

is there any way to install a gelcoat tub so it feels less flimsy and hollow?

i've lived in many rental apartments and know how poorly they hold heat and so on - but they've also been installed without much support beneath or around.

can i insulate from below with some sort of foam insulation, blown-in or otherwise?

is it preferable to install on a mortar base than wood?

other suggestions?

or, is it simply better to leap up in cost to an acrylic tub?

lastly, can anyone comment on whether Vikrell is a more substantial gelcoat product than other gelcoat products?

i appreciate your input.

best regards,


12-12-2004, 01:06 PM
If you set the tub in mortar, you essentially provide a very solid foundation for the tub, and (at least the bottom) feels much more solid. It will usually last a little longer before it gets stress cracks as well.

I've not done it, but my guess is that you could probably spray some foam sealant on the tub to help to hold in the heat. I'm not a pro, and haven't tried it. It shouldn't hurt things as long as you leave room to get to the drain and overflow assembly. that would add some insulation and perceived solidity to the tub as well.

12-13-2004, 05:44 AM
thanks for your ideas ... very helpful.

when you suggest setting the tub in mortar, are you describing the same thing terry love describes on the jetted tub installation page:

'My favorite method is to frame the tub support box to allow about an inch clearance under the bottom of the tub. Just before the tub is set into place, spread mortar mix on the floor. When the tub is set into place, it should be in full contact with the mortar for support. Putting some water in the tub will help to "hold" the tub into the mortar mix.'

if not, can you elaborate on your method?

many thanks, kavita

12-13-2004, 06:36 AM
Yes I'm sure Jim intends the directions Terry provides. I do not put water in my tubs because it can push the tub down further on the drop in units. It's not a straight mortar mix because it doesn't hold together. Quikcrete sand mix is the more common that's used.

12-15-2004, 04:21 AM
thanks for clarifying that, lonny. i'm new to mortar of any kind, and i hope you can answer another question about this.

is Quickrete sand mix already mixed to the preferred mortar-mix consistency you decribe (besides the water)?

and, will the mortar mix stay-put without a smaller frame to keep it harbored, or is it simply a thick consistency that dries fast?

thanks again ... the tub is coming in a couple weeks and i'm grateful for this installation info.


12-15-2004, 05:07 AM
I use quikcrete as it comes from the bag. An additional frame is not needed. You mix it semi-dry. Different plumbers have different preferences. Many prefer structolite. You can look up your installation instructions on the web and follow them.

12-15-2004, 05:08 AM
One other thing. I usually place a piece of plastic over the cement before setting the tub so there is no chance for the concrete to bond to the tub and prevent its removal sometime in the future.