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Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: rsihnhold on December 30, 2014, 06:57:23 pm

Title: Soft Floor
Post by: rsihnhold on December 30, 2014, 06:57:23 pm
As I'm getting closer to finishing my floor tile installation (back to front), I've been noticing that the floor is a bit soft towards the front and right down the middle.  After the old carpet and underlayment was ripped up, I noticed that you could actually hear what sounded like air moving when you stepped on the soft area, like air being forced out.  Has anyone else had this issue?
Title: Re: Soft Floor
Post by: John Haygarth on December 30, 2014, 08:15:50 pm
 It was not the sound of moisture was it rather than air?
Take some pictures of the "soft" area and post them as it would help somewhat. There is nothing really right under that section that I am aware of
JohnH
Title: Re: Soft Floor
Post by: rsihnhold on December 30, 2014, 09:22:28 pm
John,

The spot in the floor looks exactly the same as everywhere else on the floor with no signs that it has ever been wet or anything visibly different about it.  If you rock back and forth on it you can feel and hear air being pushed out somewhere and it will not fill back up with air until you step off it.  Once you've stepped off of it, you can step back on it and do it again.  I guess it might just be a slightly high spot in the plywood.
Title: Re: Soft Floor
Post by: Chuck & Jeannie on December 30, 2014, 09:23:58 pm
Is the floor made up of several layers of material?  If so, could it be a small area where the layers have separated (don't want to say the "D" word), allowing the "air" noise when stepped on?
Title: Re: Soft Floor
Post by: rsihnhold on December 31, 2014, 10:58:56 am
Yes, the floor is a sandwich construction of fiberglass and foam with plywood over the top.  I think I'm just going to through bolt the soft spot with a recessed screw/s and washers to force it together and see what happens.  It is going to suck having to get to the underside location which is just in front of where the cables and hoses pass start to enter the bays. ^.^d
Title: Re: Soft Floor
Post by: Chuck & Jeannie on December 31, 2014, 11:12:02 am
Check the area in question with a strong magnet - see if you are lucky enough to find a frame member running through there.  Might be a stronger repair if you could put a couple sheet metal screws through floor into the steel frame.
Title: Re: Soft Floor
Post by: Kent Speers on January 01, 2015, 03:29:38 pm
Yes, the floor is a sandwich construction of fiberglass and foam with plywood over the top.  I think I'm just going to through bolt the soft spot with a recessed screw/s and washers to force it together and see what happens.  It is going to suck having to get to the underside location which is just in front of where the cables and hoses pass start to enter the bays. ^.^d

Are you using ceramic tile or faux ceramic, modified decorator vinyl, tile? If you are using hard ceramic tile screwing down the underlayment may make a low spot under the tile, not a good idea. It will probably crack the tile over time. Ceramic tile needs a level sub surface. If you screw the plywood down use polymer modified thin set leveling compound to bring the substrate back to level. If you are using vinyl Tile this isn't quite as critical.

You need to use polymer modified grout. If there is any flexibility in the substrate you should not use cementitious grout. It will probably crack. There are a number of liquid polymer modifiers and powdered polymer modified grouts readily available. They will give you the flexibility needed if there is any question about the rigidity of the plywood.
Title: Re: Soft Floor
Post by: rsihnhold on January 03, 2015, 08:45:08 pm
Kent,
For better or worse, I ended up using floating floor heat mats and SnapStone floating tile.  They specify that you are required to use their ultra-flexible grout only and I'm hoping it holds up since there is quite a bit of give to the tiles sitting on top of the heat mats.  We shall see.
Title: Re: Soft Floor
Post by: Caflashbob on January 04, 2015, 12:41:36 pm
Old ftx's used to have delaminated floors sometimes in the hallways. 

Fix was to weld in a crossbar to support the floor from underneath 

Title: Re: Soft Floor
Post by: fouroureye on January 04, 2015, 05:14:22 pm
Robert, you used heat mats as in heated tile?
Title: Re: Soft Floor
Post by: rsihnhold on January 04, 2015, 06:10:18 pm
@fouroureye
Yes, the heat mats went under the floating tile floor.  I used these and broke my small 34' up into two separate zones (which probably wasn't necessary in hindsight).

Buy Electric Floor Heating - 120V (http://www.thermosoft.com/radiant-floor-heating-products/shop/thermofloor-120v/)

I'll probably create a post when I'm done with my impressions of everything.

Title: Re: Soft Floor
Post by: fouroureye on January 05, 2015, 08:48:29 am
hi, did you run separate circuits for that or did you run it out of the bathroom where did you put your thermostat and a floating tile floor?
Title: Re: Soft Floor
Post by: rsihnhold on January 06, 2015, 10:52:28 am
@fouroureye
I did run a new circuit from the show power panel.  The total wattage of the heat mats was fine for a 20 amp circuit so one circuit suffices. 

One thermostat was put in the bedroom entry and cut into the wood cabinet right below the light switch.  The other was cut into a cabinet behind the passenger seat.  The location and height wasn't terribly important due to using the floor temperature sensor as the measuring point rather than using air temperature.

Now having said all of that, I'm not terribly impressed with the actual performance of this setup.  Part of it may be that I use it in colder temperatures than most of the users here would.  There is a significant difference in floor temperature between areas that are over the top of the bay storage and areas that have no enclosed space underneath (bedroom and driving area).  Without that enclosed area underneath, the heat mats aren't able to truly heat the floor up to the normal 77F thermostat temperature once it gets below the low 40s or so and the floor heat runs nonstop, never reaching the thermostat set point.
Title: Re: Soft Floor
Post by: fouroureye on January 06, 2015, 06:26:05 pm
heat transfer is not as goo with the floating tile. The mortor is a hear sink, there are air gaps with the floting tile. Good option.. just less effective up north-then why am I here?

Title: Re: Soft Floor
Post by: rsihnhold on January 06, 2015, 06:55:25 pm
@fouroureye

Agreed about the lack of heat transfer. 

This wasn't the way I would have liked to have done it since the raw materials are more expensive than a normal tile floor and the performance probably isn't as good either (especially with the 3" spacing in the mats).  But I started the work when I was up in North Dakota and the floor temperature at the time, measured with an IR thermometer, was well below freezing in the bedroom with frost formed on the top of the subfloor.  I envisioned that I was probably going to have lots of problems with the curing of the self leveling mortar encasing the heat wires at those temps and decided to try something different. 

If I had to rip up the current setup for some reason, I wouldn't use the same system but it would probably work fine for someone who spent all of their time in the south or only used their FT during the summer and didn't want to mess with laying traditional tile.  Despite those complaints, it is functional and it certainly does keep the floor warmer than the non-heated floor at sub-freezing temperatures but I do wish that it worked better than it does.  Maybe I just had too high of expectations for it.
Title: Re: Soft Floor
Post by: krush on January 06, 2015, 10:44:58 pm
The problem isn't heat transfer up to the floor, the problem too much heat transfer the wrong way! There just isn't that much insulation in the floor. Also, you just can't get that much heat from 20amp circuits.

If heat transfer upward was a problem, the system would be shutting off because it got too hot.
Title: Re: Soft Floor
Post by: fouroureye on January 07, 2015, 07:05:18 am
the matting and the cable system are only design to heat the area that is in contact not anything else. The heat transfer is more efficient if the system is in direct contact with the tile, of wood. Thermostat is embedded in the mortar in one location

insulation down with only have affected where the thermostat is located to make heat. The uninsulated areas that he's talking about would be affected because they cool quicker because of a lack of insulation.