Tile over tongue and groove

[Juneappal]

I have a 1908 farmhouse which originally had roofed, but unwalled tongue and groove porches. (true 2"x8" joists, 20" oc, diagonal 1x10 underlay) 100 years later, it is time to resurface the porches, and my preference would be to lay down tile.

Basically, the back porch is 5'x6', the tng runs in the 6' dimension and is perpendicular to the joists. Front porch is ~30' x 6' across the front of the house. The joists are supported at each end and at the center by a supporting beam

I have tried to post a picture, but the forum keeps telling me it is a url and I should remove it.


My thought was to put 1/4" cement board (durock) on the tongue and groove, then 12" porcelain squares (rialto, from Lowe's) on the durock. I typed some number into the deflecto, and depending on how I misinterpret the questions I either get two thumbs up or two thumbs down. Will this approach work?

Here's a picture of the back porch:

 

[GazTech]

It looks a bit rickety,if it is sound then screw 12mm backerboard down at 300mm centres and tile in BAL fastflex,then grout in wide joint grout with GT1 polymer additive ,hope this helps🙂

 

[Juneappal]

It looks a bit rickety,if it is sound then screw 12mm backerboard down at 300mm centres and tile in BAL fastflex,then grout in wide joint grout with GT1 polymer additive ,hope this helps🙂

Would the same method work on the front porch which is the same depth away from the wall, but spans 30' across the front of the house? (I am concerned because of what I have read elsewhere about joist deflection)

 

[DHTiling]

With it being external location i would strip of boards and put 25mm marine ply down screwed down with brass screws at 200mm centres for extra strength and tile with bal- fastflex and grout with bal wide joint and gt1 additive...........

 

[GazTech]

With it being external location i would strip of boards and put 25mm marine ply down screwed down with brass screws at 200mm centres for extra strength and tile with bal- fastflex and grout with bal wide joint and gt1 additive...........

I concurr

 

[Juneappal]

And not worry about deflection at all?

 

[GazTech]

And not worry about deflection at all?

Try this,place a pyrex mixing bowl full of water in the middle of your porch.Stand at an end about 3ft in,jump and see if there is a ripple,if not no problem,slight ripple,no problem.If you jump and the water leaves the bowl,then maybe we will address deflection🙂

 

[DHTiling]

if there is deflection , you will need to support the joists from underneath, also worth putting noggings in between joists so u can get extra fixings in sub-floor...