Waterproofing the earth sheltered home

When burying your home, structural strength is probably the most important thing, but a close second is waterproofing.  My home will feature a number of layers of waterproofing (belt and suspenders analogy), but this layer of Blue Max liquid rubber is probably the most important.  As usual, I did make some mistakes and we can get to that later, but first…

The Video:

Not Cheap:

I had used a different waterproofing on the basement that I have since concluded was totally inadequate.  That stuff cost about 255$ per bucket.  I decided to switch to Blue Max after seeing it done on another earth sheltered home I was involved with.  The Blue Max costs 100$ less per bucket, but it goes on much thicker, so you get fewer square feet per bucket. Also, I had to buy a whole pallet to avoid shipping costs and get a bulk discount.  I calculated that the whole pallet should take care of most of my surface area according to their coverage estimate…  but with all the lumps and bumps and holes due to the rough shotcrete surface, we used it up at about double the rate and I will need a second pallet for the rest of the house.

Rained Out

An unexpected and very heavy rain storm washing away our work.

Getting rained out that first day only made matters worse.  Expensive water proofing was being washed off the house and the day was shot…

But it turned out to be only a moderate disaster.  Only some of the waterproofing really washed off, so the second layer went on nicely. Also, the lift rental company (Wolverine Rental) were really nice guys and let me keep the lift for free for a few more days to make up for the rained out weekend.

Finishers:

Basically, you have part of the crew shooting the shotcrete, and they need to keep moving to keep up with the concrete trucks.  They can’t really stop to smooth it out.

When they are available, my Shotcrete guy charges an extra few hundred dollars per day per finishing guy.  These guys come after the gunner crew and trim off the excess and generally try to smooth it off.  Maybe “smooth” is a bit of an exaggeration, but “shaping” it does help to get rid of the worst lumps and bumps and splashes and slumps (if Dr. Suess did shotcrete).   The expensive waterproofing goes twice as far on the smoother walls and the savings quickly pay for the finishing guys…  Plus the smoother walls just look better and probably shed water better, etc.

So, paying for the finishing guys is a no-brainer. My only problem is that the finishing guys are not always available.  I was only able to get them for 3 out of the last 8 shotcrete days I have had.

We had a finisher on site when we shot the right side, but none were available when we shot the left…

Bad timing:

As you may tell by the fact that I thought I could build this house in 18 months, I am an optimist. Optimists are generally much more pleasant than pessimists (or “realists” as they call themselves), but we do tend to get ourselves in trouble from time to time.

In this case, I thought that I would be able to get the next couple shotcrete sections in so I could bury the house before winter…  Winter came early and that plan was derailed.   Spring brought its own scheduling problems and now it is mid summer and we are still waiting on shotcrete.

This has left me with a problem of long term exposure to UV…

Ultra Violet Damage

UV rays destroy most things, especially insulation and rubber waterproofing.  The Blue Max guys say I should get their product covered (buried) within a month.  I couldn’t.  I did try covering it with large sheets of 6 mil black plastic, and I am sure that helped, but I had to fight with winter storms to keep that on.  It has been a long time and I am seeing some signs of damage, but fortunately not nearly as dramatic as what is happening to the rigid insulation.

A zoom in on the surface after months of UV damage. You can see the little cracks.

Paint Brush

Because of the lumps and bumps in the unsmoothed shotcrete, getting full coverage was very difficult.  Sherri was doing touch-ups with a paint brush long after I was done with the sprayer.  By the time she was done, we had only one single bucket of Blue Max left…

Sherri went back over most of the structure with a paint brush to get around all the little lumps and bumps… Using up even more Blue Max.

Gallery

As usual, here are a bunch of pics to round out the story.

An unexpected and very heavy rain storm washing away our work.

The rain washing away rivers of expensive (and probably polluting) Blue Max.

Here is the Quonset after the rain washed off our fresh waterproofing before it had a chance to set.

Here you can see the Quonset with a nice thick layer of Blue Max

Another pic of the Quonset

The space between these arches will eventually become our kitchen…

Here, I am troweling on some hydraulic cement to fill holes in the surface that would have used up too much Blue Max. It looks like a set from Star Wars.

Gravity pulls the shotcrete down and away from pipes and boards before it sets.

I chisteled away the shotcrete near the skylight curbs and then filled these voids with hydraulic concrete.

The wasps around here are huge… And the lift was very helpful.

Other times, we would just shoot from the top of the building. We all ruined our shoes.

It is much easier to spray from the lift if someone else is driving it. Here, David operated the lift so Hunter could spray.

The lift made the job much easier.

Bedrooms are waterproofed

The HDPE french drains were dug in and sloped properly before being covered in pea-stone.

Here you can see how much of the concrete rebound we had to chisel away while laying the drain.

French Drain, ready for Pea Stone. The sand is already very permeable, but building code in our area calls for Pea Stone anyway…

Here, the french drain is going below the plumbing and electrical

Here we are taking buckets of broken up shotcrete that was spilled inside while shooting the bedroom walls.

David approves

David had a bit of fun delivering pea stone in the skidsteer.

Dan testing his welds with some chin-ups.

At the end of the day, we had 2/3rds of the structure waterproofed…

Sherri went back over most of the structure with a paint brush to get around all the little lumps and bumps… Using up even more Blue Max.

At the end of the day, we all went up in the lift and got some photos.

The BlueMax changed the feel of the shotcrete and the boys enjoy hanging out up there…

We had a finisher on site when we shot the right side, but none were available when we shot the left…

A zoom in on the surface after months of UV damage. You can see the little cracks.