A preview of chinking

It was still wet in this picture – looks like a river, though.

The setup

I installed the rim joists- they are 2×12’s that are lag screwed to the inside perimeter of the home, and they provide a place for the floor joists to hang from. While installing them, I noticed some of the rim joists ended up being higher than parts of our first row of logs. Our logs are very tapered, which means some of them are 28″ on the bottom, and 12″ or sometimes a bit less than that on the top. I started wondering, “if the rim joist is near the log at this point, how am I going to chink after I put the subfloor in? Maybe just spray foam at those points?” I discussed with my wife. She thought we should go ahead and chink just one row for now. That way, when the subfloor is installed, we can butt it up against the logs and/or the chink and not worry about how to chink later. Not everyone does this, but we decided it would give us a consistent look. So, the floor joists are on hold while we chink one row.

Plus, we thought chinking one row will give us an idea on what tools and equipment we’ll need to start looking for now so we’re ready when we ramp up to chinking the whole house.

Preparing to chink

LHBA uses a secret recipe for their chink. It is made out of Portland cement, sand, and lime (garden lime works fine). It is closer to what was traditionally used for chink on log homes than anything out there on the market. The ratio of the ingredients is the secret. While researching this post, I found a lot of myths out there regarding mortar chinking- that it retains water (it doesn’t – how could it? it’s cement – does your driveway retain water? no.) Or that it will crack – wrong again- here’s a picture of a LHBA home with 50 year old chinking. This is after the home went through a 6.8 earthquake:


picture from LHBA article on chinking

Most other types of log homes you’ll see have some kind of latex or silicone-based chinking that contains sand or something to give it the look of traditional chink. Based on their calculator, I’d need about $14,000 of the factory stuff:



LHBA recommends against latex/silicone types of chinking for a few reasons:

  1. Very expensive.  I can buy as much sand as my trailer can carry for under $20. Two trailer loads ought to do it. Lime is $3 a bag, but I might find it cheaper at some big farm co-op somewhere. The portland cement is a bit more- like $14 for a 90 lb bag. I’m about halfway through my first bag, and I dropped a lot of mortar on the ground during my learning curve. I still need to do the outside, but figure just over a bag per row times 15 rows. So that’s the expensive part. So maybe $500 for chinking.
  2. Bad for the logs. Silicone and latex chinking products are water phobic, so they keep the water out – of themselves. It’s possible the water can become trapped behind these treatments and pool up, and then not have a way to drain away. They definitely don’t let the log breathe like it should. Real mortar chinking is natural and it breathes and allows moisture to drain and evaporate. Which is great for keeping the logs mold and mildew-free. And not rotting.
  3. Easy to apply? I’ve seen a video where a guy slaps on real cement mortar chinking – he does 10′ of chinking in about 20 seconds. I’m not that good. But it’s only row one – give me a minute, ok? 🙂

Knowing all this, I’m not sure what the appeal is for the latex/silicone based chinking.


I needed some masonry tools, of course.

  • I bought a little 2″ trowel, and then rounded the corners as instructed by the fine folks on LHBA. Round corners makes it easy to smooth out the chinking.
  • a mortar board.
  • a kitchen spoon (thanks Shark!). yes really.
  • stucco lath, stapler
  • lots and lots and lots of nails for my nail gun.


  • portland cement
  • sand. in bags for now. probably buy a pile of it. My daughter is looking forward to a pile of sand to play with…
  • garden lime.
  • a mixing bucket. When we really get going, I’m already on the lookout for a cement mixer.
  • stucco lath for the really big gaps (>5″). (“your cabin has gaps that big???” yes. As they say, if you can’t chuck a cat through your gaps, it ain’t a real log home).
  • insulation
    • That bag of glass wool I found on the side of the road…
    • and some Rock Wool – the rats hate it. None of that pink stuff. I hate that stuff- itchy. used to hate it at the phone company when I had to crawl up in a ceiling stuffed with that nasty pink stuff.


  1. insulation
    1. 20200507_181316The glass wool is really nice- it has the texture of soft cotton. Just stuff it in there until you have enough that there’s a somewhat firm surface for the mortar to stick to. Or use Rock Wool (not as nice, but more rat resistant) – get the non-paper backed kind. Cut it into strips and stuff it in there. Ideally, you have insulation on the indoor side of the logs, and then another separate run of insulation on the outdoor side, with an air gap between them. With my crooked logs and their gaps- just do the best you can.
  2. nails
    1. ka-chinkI used framing nails. Hot Dipped Galvanized (HDG) if you can afford them, but anything will do. Probably 3″ is best. And a nail gun. With a modified “Ka-chink” nozzle on it (thanks Rod and Ronnie): A rubber hose about 2″ long fits over the nose of the nail gun (or I used a piece of pvc pipe and a compression clamp), which holds it away from the log so the nail only goes in about an inch.  The rest of the nail is then bent vertically to hold the insulation in place.
  3. sometimes lath
    1. For big gaps. Cut to size and staple in place.
  4. mortar
    1. slap a big pile of mortar on the mortar board and slide or slam it into place with the trowel. don’t work it to death- slap it in, and try to smooth it only once. Let it dry some, then go back if you want to make it nicer by smoothing it some more.
    2. My wife had her doubts- the mortar goes on really dark. But it turns a very light gray when it is dry, so she felt better about it at that point.


I had a terrible time on my first try- my mortar was too wet. It’s actually kind of comical:

1st try – fail.

You actually want it to be surprisingly dry so it can hold itself up. But not too dry- it won’t hold together. My wife made an excellent video of the whole process:

2nd try – much better

I’m really excited about the results. With my curvy logs, the mortar looks like a river flowing between the logs. It is really neat looking, and totally custom. It is definitely a one-of-a-kind log home. And not in a bad way. It pops.


Next Steps

Floor joists. And then the subfloor. Really really. Then I can roll the scaffolding around in there. Besides, I need to cut out doors and windows before I do any more chinking. But it was really good practice on some areas that will probably never be seen.

3 thoughts on “A preview of chinking

  1. What are the pros and cons of polyurethane foam? It would seem to be a perfect solution to chinking, go in faster and provide another level of seal between inside and outside.


    1. I’m not an expert. I imagine it would be expensive to buy. I know in my area, I have to pass what’s called “a blower door test” before I can get an occupancy permit. Someone from the utilities company comes and basically hooks a fan to the door and a pressure gauge, then they see how much air leaks out of the house. I think my house has to pass less than 5 air changes per hour, whatever that is. So whatever you use for chinking has to be tight enough to pass that test. The other thing is the R value of polyurethane. The rockwool I’m using says it is R30. R15 is the minimum.

      Flammability would be my concern, and would probably be a show-stopper for the code guys. You’d probably want to be sure about that before using it in your house.


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