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Ceramic and Porcelain Tile Expert Answers failures Grout installation Leak Moisture Problems Movement Joints Standards Waterproofing Wet Areas
Why is my Tiled Balcony Leaking and How Can I fix it?
QUESTION
I have a 500 sq. ft. balcony with terracotta tiles that for whatever reason were not sealed. Water has intruded into cracks that have formed over a three year period, some as wide as 1/16”, but most are small micro cracks in the grout as well as the tile itself. The result has been rain water intrusion into the sub-structure of the wooden balcony support system, which I am afraid that over an extended period of time will cause damage that may call for structural repair. The balcony structure consists of 2 x 12 wood joists @ 12" o.c., covered by 3/4" ply-wood sub-floor. A peel and stick moisture barrier is properly installed over the sub-floor and and the adjacent vertical walls from the balcony edges. Three inches of fiber mesh concrete was poured over the peel and stick to form the floor. The terracotta tiles were installed over the concrete using the proper thin set and grout. Leaks have appeared in areas near the bottom of the joists at their connections to the ridge boards going along the front, vertical surface of the balcony. The intrusion is in the tile cracks. Can this be stopped with a sealant, or do I need to remove the entire tile floor, grout included, put in a membrane on top of the concrete, and re-tile. The concrete is only 2500 psi fiber mesh. I am afraid of damaging it if I remove tile with a demo hammer. I would have to chisel out each tile and then use a diamond embedded circular grinder plate to grind down the thin set. Please Help!ANSWER
ANSWER - When there is a problem it normally is not due to one deficiency, but due to multiple compounding deficiencies.You state that the peel and stick moisture barrier was properly installed. If if were properly installed it would not be leaking. If in fact it was installed properly, then something structural would have had to happen to cause a breach in the waterproof membrane to allow it to leak. Or perhaps after it was installed and before it was tiled over, something happen that caused damage to the membrane?
Bottom line, is if there is a leak, then the membrane isn't working for one reason or the other.
Cracks in the grout joint won't cause a leak in the underlying membrane. Cementitious grout is porous so water does go through it whether it has what sounds like shrinkage cracks, or stress cracks due to not having adequate movement joints installed.
Sealers over tiles do not make them waterproof. Even if the tile had been sealed it would not have prevented the leak.
You should have movement joints in the installation to mitigate stress caused by the tile expanding when wet or when it heats up, and contracting when it cools and drys. A movement joint is a grout joint with a polyethylene closed-cell backer rod with an ASTM C920 sealant (100% silicone or urethane). There should be a movement joint at the perimeter of the installation at all transitions, and every 8' to 12' in all directions.
You should have drains on the balcony. Either a drain within the balcony or having it drain off the side of the balcony that has a drip edge flashing so it doesn't stain the side of the building. Not only should the surface of the tile be sloped to the respective drains at the rate of 1/4" per foot, but the surface of the underlying peel and stick membrane should be sloped to a drain weep system at the rate of 1/4" per foot. If there is not adequate drainage at the waterproofing surface then in effect you are creating a reservoir of water that can't escape.
The only way to properly fix it is to remove the tile assembly to find the problem and fix the problem. Otherwise you are only treating the symptom and not the problem.
Some repair options that will not fix the problem, does not meet industry standards, and may or may not solve the problem are:
1. You can remove the tile from the 3" fiber reinforced concrete. If you do it carefully and if it is structurally sound, you can remove the tile so you can re-use the concrete base. You might have to patch some divots from the removal process. Prep the concrete and the apply a liquid applied waterproof membrane meeting ANSI A118.10 over the concrete and up the walls. Then install your tile over it.
2. Remove all grout from the tile installation and fill them all with backer rod and an ASTM C920 sealant. Make sure the perimeter joint is done too. Tool the joint to a concave shape so it doesn't get dirty from walking on it. Depending on how porous your Terra Cotta tile is, water may still be able to pass through it. In theory, if you use this type of sealant in all of the joints, it makes the joints watertight, it gives you movement joints in all joints to mitigate potential movement stresses, and it gives you some additional bonding strength between the tiles.
6 thoughts on “Why is my Tiled Balcony Leaking and How Can I fix it?”
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I am in the same boat. I have 420 sq. ft newly built balcony. I have playwood installed on top 2X12X16 joists @ every 18 inches. I have applied Black-Jack Rubber Coat #57 on Plywood and I sealed joints with Tape. on top of Hardy contractor used Red guard and Mapelastic Aquadefense coat than porcelain time with grout. I have tested by pouring water on tiles and not allowing water go down at the edge. I see dripping the water bottom of the edge (ceiling edge). I am sure of this. I stopped water going down and just staying on the floor.
How to fix this kind of issue. Can I apply a clear ASTM C920 sealant on grout lines? Will that works?
Redgard and Aquadefense are both liquid applied waterproof membranes. Doesn’t make sense that you used them both over the Hardibacker board.
If if fact you did waterproof the hardibacker board correctly, then likely the water is getting in from the perimeters or other transitions. You should have run the waterproofing up the wall at least 3 inches to be safe. Those transitions normally require a reinforcement fabric to be used with the liquid applied membrane.
I would test all of the perimeter areas and transitions to make sure they are watertight. Then flood test the deck again. If you can verify that the transitions are watertight and you still have leaking, then maybe that is an indication that the waterproofing wasn’t done correctly within the field of tile. In that case you could try using the ASTM C920 sealant, but not over the grout, but remove the grout and then fill the joints with the sealant.
Hi. We have a painted rendered brick veneer house with an uncovered balcony at the front that sits above two bedrooms on the level below. Construction of the L3 balcony is of timber framed flooring clad with compressed fibre cement floor
lining and ceramic tiling incorporating a Colorbond facing panels surrounding the balcony floor frame. Due to ongoing water leaks over 9-10 years the balcony tiles & grout, waterproofing and concrete screed have been removed three times using a jack hammer. The ceilings/insultation in the two bedrooms below have been removed to help identify the site of water penetration. the compressed fibre cement floor lining that sits on the timber joists has multiple signs of cracking adjacent to the joists and there are two holes where the splade of the jack hammer has penetrated it. Should I be concerned about the vibrational damage this is causing to the house? Also there are gaps between the Colorbond facing panels surrounding the balcony floor frame and the exterior masonry walls. Is this a concern?
All of it is a concern. If it has been redone 3 times then it was done wrong 4 times. First of all the framing has to be structurally sound. There should be no more deflection that L/360, which may require installing bracing between the floor joists. The the underlying substrate has to be properly sloped to a drain or to a gutter of drip edge off of the balcony so it has a clear path to drain away from the house. The structural substrate has to be properly waterproofed with a primary roofing waterproof membrane that flashes up the sides of the adjacent walls. Then a mortar bed or setting bed must be installed over the pre-sloped waterproof membrane maintaining the 1/4″ in 12 inches slope towards the drain. We always add a secondary tile waterproof membrane over the tile mortar bed or backer board and flash it up at least 3″ up the adjacent walls. The balcony has to be waterproofed just like you waterproof a shower pan to contain the water and to design it to evacuate through a drainage system. Then you bond the tile to the secondary waterproof membrane. You grout it with an appropriate grout. You install expansion joints at the perimeters and every 8 to 12 feet in each direction with an ASTM C920 sealant such as a 100% silicone or polyurethane.
If you do right it will perform and last ….
I have a tile balcony that wraps around the fireplace of the house. It has been recently refinished with all the things mentioned above. Plywood, then waterproof membrane, then concrete base, thinset and then tile with epoxy grout. It is 20′ x 15′. The only place it leaks or drips is at the flashing on the end of balcony 15′ from house. It will do this after heavy rain and then drip several days afterward in the mornings like condensate. I suspect the fireplace, but it looks fine and sealed around roof. I have not checked the chimney cap and so maybe that will be next. I should also mention that this also occurred on the first installation. I can not imagine that much condensation building up under the tile. I appreciate your feedback.
If you have a problem and don’t first identify and remediate what caused the problem, then you are likely to have the problem reoccur.
You might have all of the right components for a proper installation, but if you aren’t using the right products and/or not installing them properly, then you are likely to have problems.
To understand what is causing the leaking condition, you need to have someone like CTaSC do a forensic investigation by strategically removing various tiles in a careful manner and to inspect and evaluate the underlying conditions.
In theory, if you properly install an epoxy grout it should make those joints water tight, but not waterproof. If those grout joints are watertight then the water is coming in from another source rather than through the grout joints.
Since the water is dripping from the edge flashing of the balcony, that might be because water is saturating the underlying mortar bed under the tile and the water is migrating to the edge and weeping out of whatever open path is there.
The solution is either stone water source, or repair the breach where the water is coming out.
Normally for exterior decks we want a pre-sloped substrate that we waterproof with a primary roofing membrane, particularly if it is over occupied living space. We would flash the waterproof membrane up and adjacent walls or fireplaces. We would float a mortar bed with a slope to a drain or to the outer edge of the balcony. We would put a gutter or a drip edge flashing so water doesn’t splash on the sides of the house or deck. We would apply a secondary waterproof membrane over the mortar bed to keep water out of the mortar bed. This keeps it lighter and helps prevent water collect in the mortar bed picking up minerals and the weeping out and precipitating the efflorescence staining.
All perimeters must be caulked with an ASTM C920 sealant to act as movement joint and to keep those joints watertight. If you use the products properly and install them properly you should have a successful installation.