Upon close inspection I was able to determine that the blocks themselves were somehow affixed to each other, which is what I expected, however, the capstones, if that’s what they are called, are all loose. You can easily lift them off the retaining wall blocks. That seems incredibly dangerous since someone could step onto the capstones thinking they are attached and come crashing down to the ground 2 feet below.
Perhaps they weren’t attached for a reason. I live in a very cold climate and -20 degree F weather in the winter is not unusual, and it can get up to 90 degrees F in the summer months. So they may not have affixed them to the wall blocks to keep them from cracking due to temperature variations throughout the year, however, I’ve noticed other walls in the area have their capstones firmly affixed to their walls, so I’m confused.
Should I go ahead and attach the capstones to the blocks underneath them or just leave them be? And if I should attach them what should I use to ‘glue’ them down? Any thoughts would be appreciated. This is my first house with a cement block retaining wall.
Your local hardware/home improvement store should sell ‘Landscape Block Adhesive’ - usually comes in a tube and is applied with a caulking gun. There might be a more generic general purpose construction adhesive that’s compatible with masonry that would also work and might be less expensive. I’ve used the Loctite brand adhesive before with good results.
The lower blocks likely have some type of keyway that interlocks them. I don’t see any evidence of mortar holding them together. You could just get rid of the capstones, since they don’t really serve any purpose other than being decorative. To fix them firmly, I’d use mortar, rather than caulking, but I haven’t tried the stuff recommended above.
I built a similar 3 foot wall about 15 years ago and as Chef Guy notes, the lower blocks interlock. On mine I used construction adhesive to hold the decorative capstone to the wall. I did a quick check and the sources I found all still recommend it. Home Depot says just use standard construction adhesive.
As you note, if the capstone is loose, there’s a real safety issue if someone steps on in and it shifts under them.
Mortar may be an option, but I think the construction adhesive is quite cheap and very easy to apply. There is no mixing etc and you can do the whole wall in a few minutes. Over a few years the glue becomes brittle and then cracks and fails and needs to be replaced. Should be easy peasy.
Mortar for waterproofing in places that don’t get pushed or shoved. It has no strength in tension. Even modern high-tensile strength mortar breaks apart if you pull at it.
I have mortar holding the capstones on my roof. We don’t walk on them.
I have no experience with those landscape blocks, but I have a number of flagstone retaining walls - none of which are mortared. None of my walls are in the least bit unsteady, and there are some places that I step on regularly. I’m just asking, even tho they are not affixed, how unsteady are the capstones? Just because you can lift them does not mean they would slip if someone stepped on them. This may not really be a problem.
Of course, I repeat, I have no experience with these stones. And I can’t imagine the adhesive being any problem. Hell - you just bought a new house. Might as well have ANOTHER UNANTICIPATED THING to spend $$$ on!
Yup. After a few different stone walkways repairs of varying success, I asked a contractor what I should use, and he recommended the Loctite PL500. That stuff is bulletproof, I’ve never had to do a second repair where I used it.
If your 2 foot high retaining wall were 4 foot high, it would be our wall, down to the unsecured capstones. The fact that the capstones are “loose” has never been a problem for us, although it’s never been a feature, either.We have hostas (Plantain lilies) planted behind them. The shaded crevice between the hostas and the capstone is snake city!
This is exactly what worries me. I have 2 grandsons, both under 6 years old, that visit me and I can assure you someone is going to get hurt running around the backyard if I don’t secure them. Besides, why wouldn’t you secure them? It’s not like I am ever going to have to move them somewhere else…
As I see it, a stone that is an inch thick and 10-12" deep overhangs by maybe 1-2". The stone prolly weighs 20#. I’m no physicist, but for someone to get it to tip, they’d almost have to be trying to - teetering on the extreme overhanging edge with their weight leaning backwards over the overhang.
Sure, little kids (and adults) do stupid things all the time, but they’d only fall 2’. Even if it is affixed, they could still fall the 2’. Good thing small kids pretty much bounce. You are fearing that they would tip the stone, fall 2’, AND the stone would fall on top of them? Seems like a pretty remote possibility, but we each have to decide what precautions we deem reasonable.
I was offering my experience w/ flagstones - admittedly a different material and lacking even the minimal overhang your pictures show - and offering my opinion that it is not likely to be a significant issue. But if it gives you peace of mind and you have the time and money, go ahead and glue them down. Only reason not to would be if there was any possibility that you might eventually wish to dismantle the wall and use the materials elsewhere. And you say there is zero chance of that.
From how you described the new house on the other thread - on a canal, with access to boats - I bet I could walk around your home and pretty quickly identify a good number of “potential hazards” at least as significant as this one. But like I said in the other thread - looks like a lovely house in a wonderful setting. Do whatever helps you enjoy it as much as you can!
