Well, here's the second year of the house project. I flew back on Sunday May 5, and
it's taken me until the 30th to get enough done to feel it's worth a new photo. The interesting
news is that we've decided to change from the
TJI Joists specified in the architect's drawings to
Hambro's D500 system of concrete and steel joists. This will make the walls about 8" higher
for each floor to accomodate the 16" height of the steel joists that are appropriate for
our project. While this wall height will permit an 8 foot ceiling with gypsum board fastened
underneath the joists (which I'm sure a bank will like), rather than using the gypsum board,
we'll likely paint the joist steel with a fire resistant intumescent paint similar to
A/D Firefilm III and
stain the bottom surface of the cement slab above it, like we plan to stain the top surface
of the cement slab for the floor (but not necessarily the same color). This will have the combined
benefits of 16" extra air space overhead, no installing or mudding gypsum board overhead, and a
built-in easy place for hanging holiday decorations. At our request, Hambro will be designing
the roof slab to be strong enough to have a "green roof" type of protected membrane roof system
in a manner similar to the one described in this
PDF from Dow Chemical Co., who I'm sure would like to sell us styrofoam boards to insulate
that roof. As a co-worker of my sister's pointed out, a garden on the roof will be much safer
from hedgehogs. The Rastra block have been going up fairly nicely, and we'll likely be done
with the walls well in advance of the arrival of the steel joists. The curved walls make for
bigger gaps between the blocks (even with having beveled them), and we're using a lot more
of the foam glue than anticipated. I bought
Powers Triggerfoam for the next bunch of glue. It was recommended to me at the former
Rastra plant in NM, and it has product
fire & health safety
information that is fairly easy to learn about online.
Now the walls that will be completed before we bring in the steel joists are done.
As the result of a choice we made about the garage footer, the forms for the garage
frost wall need a vertical spacing of 12" instead of 15" for the concrete. We ended
up using the beveler to cut the middle out of the blocks. Sadly, the small chain saw
we had purchased for trimming edges with the beveler wasn't up to the task, so I
drilled the appropriate holes in the bar of the other saw we have and used it.
This is working, but the result is a lot less consistent than it looks when the cuts are first
made. We've decided that frost wall is going to look its best after we've buried it. Here's
the state of construction on June 19th. We've put some pallets, insulation boards, and tarp
over the stairwell so that we can keep the rain off some hand tools. Previously, we had been
using my old Bronco (It's in sad looking shape, but where's the first car you ever owned?)
for that job. The stairwell is much more spacious and convenient. As I type this it's June 25,
and the fireplace support you see laid out on the basement floor is complete up to all but the
top row of blocks. The top row is waiting until we mark the inside of all the exterior walls
with the laser level. We'll be cutting about 4" off the inside of the exterior wall forms so
that the inside of them doesn't interrupt the floor concrete from joining the wall concrete.
We'll be similarly modifying the frost wall in the garage. The joist layout drawings came from
Hambro for approval last Friday, so hopefully we'll have the joists here in about seven weeks.
I had a phone conversation yesterday (August 2, 2007) from which I learned that the steel
joists will arrive Monday, August 27. I'll be at home in WA the week before, ostensibly to
activate the replacement for my expiring debit card, but I'll also be attending a memorial
for a friend who died during the end of May and visiting with a nephew I haven't seen in a while.
Back at the start of June, the honeybees living in the old house swarmed again, providing an
example for the words I read in Wikipedia that colony collapse disorder isn't a problem for
feral or organically raised honeybees, just for commercial bee farms where, coincidentally,
the bees are fed protein supplements.
Here's a photo from July 14, 2007 of the 6" diameter holes I drilled for connecting the basement floor
to the walls. In the background, you can also see the top of the fireplace pad support and the cut I
made on the inside of the basement wall Rastra where the bottom of concrete for the floor above will be.
Then, we used some 2x10s to cover the holes and contain the concrete. The cross pieces are held in place
by pieces of 1/4" all thread going through the middle of the nodes in the Rastra that form the gaps in
the concrete grid. This construction looks typical of installing a ledger beam for holding up floor
joists. The difference here is that the 2x10s will be coming back down once the concrete in the walls
has hardened and the garage floor will be directly supported by the Earth. The landing at the top
of the stairs will be supported by the walls, however. The new things visible in the background of this
photo are the top ends of the pieces of aluminum plank grating I got for making the treads of the
basement stairs. As there's no other access to the space behind those stairs, my sister wanted them to
be able to lift up, so I'm welding up a stairway out of aluminum. It'll be nice, I think, to use the
familiar construction methods from my work on part of the house here.
Well, as you can see, the physical construction is going pretty slow right now. Once the floor joists
arrive, things will speed up a lot. We'll be racing against Wintertime.
September 12, 2007
Here's a report of some of the further progress. I'm being a little bit lazy and linking some of
the photos to text rather than to smaller images. Here's
a photo of what I made to anchor some coupling nuts into the wall. I wanted to make the wood of the rough
bucks removable, in case it got damaged during construction or a desire for other wood were to occur in the
future. Here's a photo of a few of the anchors in
the wood standing in for the bottom of the door buck in the doorway from the garage to the basement.
The steel joists arrived in good order on the morning of
August 30th. There was a little bit of confusion between six of our beams and six belonging to someone else,
but I called that day, and a truck from Quebec arrived the next afternoon dropping off the correct beams and
picking up those that arrived by mistake. We carried the joists for the basement in on the 30th and the
following day started building the form walls we had left down in order to permit that carrying.
Here's a photo and
here's another taken part way through lifting one of
the joists onto the newly built form wall. One of the nice things about the Rastra form blocks is their
compressive strength, which allowed us to stack up scrap pieces in order to lift the ~200 lb joists in smaller
increments. Finally, here below is a photo of the basement I took on September 9th.
Here's a few more photos of setting up the bond
beam and putting the beam over the doorway in the partition wall in the middle of the basement.
After I thought we were about ready, I started vacuuming out all the dust that had gone
down into the forms. Cutting out the nodes for the bond beam especially let a lot of it
go down there. The big end of a piece of 1" electrical conduit fit around the leaf blower
nozzle that came with the Craftsman Blower Vac, and I used that to reach to the bottom of
the forms for the vacuuming. It worked best without direct sunlight as the flashlight
that was necessary to see the bottom couldn't compete very well when the sun was out. The
vacuuming took more than three days. As I went along, I did final placement of the vertical
rebar, trying to use it to help hold the horizontal rebar more closely to the middle of the
holes. The challenge of doing this in the curves, led me to the understanding that it would
have been impossible to do this sort of curve construction if the curves hadn't been circular
sections. In turn, this understanding led me to consider
Autoclaved Aerated Concrete as an alternative to Rastra for building my own house later on.
When using the common construction method for AAC, all horizontal concrete is in the form of
bond beams, so horizontal rebar can more easily be properly placed in non-regular curves.
Once I had the vertical rebar placed, I wire tied the extensions to it for tying the basement
wall the the next wall above. When that was all done, I went back around and wire tied in the
bond beam rebar, tying it to the horizontal supports to control the spacing, and tying it to
the #6 vertical rebar in those places where two of them occupied the same hole. In the meantime,
I had purchased one of Oztec's Rebar
Shaker concrete vibrators as, not having contractor's insurance, we were having trouble
renting one. Here's how it all looked on the morning of October 7th, the day of the basement
During the pour, Steve went around placing the concrete, and I followed behind, vibrating.
Raimona, not wanting to work near the tops of the walls, did everything on the ground, placing
and smoothing the concrete for the floor in the stairwell, filling the bottom of the window frame
of the escapement window, and trying to make up for our lack of cleanliness preparedness.
The wall pour was successful in every way where we were thinking it might fail, but was
unsuccessful in ways whose thoughts weren't in the forefront of our minds. This unsuccessfulness
was a great dampener of spirits and made the project longer by more than a month. It's
the primary reason that I didn't update this website until mid-January 2008.
First, here's the problems we were concerned about but didn't have:
Now here's the things that we didn't prepare for enough, that bit us in the ass.
- Blow outs due to vibrating the concrete
- We had been warned by several people in conversation, and I had read a few comments online
suggesting that vibrating the concrete would create more pressure than the forms could
handle and cause them to blow out. Using the Rastra forms and the Rebar Shaker, this didn't
happen. So far as I could tell, it didn't come close to happening.
- Blow outs due to wide gaps between the forms on the outside of the curves
- We had gaps up to an inch wide between the forms in some places on the outside
of the curves. We were concerned that the foam might not hold the concrete in, since
these gaps ran the vertical length of vertical columns of concrete. To prevent this,
we coated the lower part of outside of the forms with Conproco Foundation Coat, a fibre
reinforced waterproof surface bonding cement, and this strategy worked well. Raimona did
the lion's share of the coating. We had no problems with concrete blowing out at the wide
- Rastra being crushed by the weight of the joists and plywood while undergoing the
stress of being filled
- We had some concern that all that weight might cause the Rastra to fail, but with the
15" long 2x2's under the ends of the joists, it didn't, even when quantities of concrete
were stored on plywood adjacent to the 10" partition wall.
- We had been warned online and by the engineer that there was some chance that the walls
might fall over while the concrete was being poured.
- Perhaps the presence of the joists and the beam across the end of the stairwell helped
them support one another sufficiently. Perhaps it was another reason. This didn't happen.
I saw no indication that it was even trying to start to happen.
- We had concern that where the basement walls met the two foot lower garage frost wall,
the concrete might flow out while the final round (lift) of the pour was happening in the
- The concrete in the garage frost wall set up quickly enough to have prevented this,
even if we hadn't had the troubles we later did.
- We had concern that if we cut holes in the Rastra to check the height of the concrete
as the pour went along, than the freshly glued plugs in the holes wouldn't be strong enough
to hold back the concrete during the next lift.
- So, we didn't cut any holes. While guessing seemed to be working, we did learn that
trying to use a stick to probe the height of the concrete in the wall didn't work, and
neither did using a flashlight.
- There was some concern that using 1/2" crushed rock rather than pea gravel would
prevent the concrete from flowing everywhere properly.
- Using the vibrator made this not a problem, allowing us to use an aggregate with an
irregular surface that forms a stronger bond. No voids were found in the concrete that
was delivered at the proper slump.
A while after the pour, Raimona and Steve went around the house with cordless drills and
checked every 15" horizontally and vertically for voids. Then, Steve checked more closely
where they were found and marked the edges of the voids with s spray can of bright marking
paint. It took a long time to find him, but we found someone with a trailer pump that
could help us with filling in the voids. We used pure grout (cement and sand, but no
larger aggregate) for this, and a yard and a half did the whole job. To direct the concrete into
the voids, I cut 3/4" plywood into squares big enough to be fastened to the Rastra using all-thread
that passed all the way through the wall at the nodes. I cut holes in this the diameter of
the outside of 4" drain pipe. Then I cut up pieces of the plywood into smaller squares
and cut the same holes in those. I fastened drain pipe elbows into the smaller pieces, screwing
through nipples of drain pipe glued into the elbows. Finally, I had other small squares
of thinner (1/2") plywood with the hole sawed plugs screwed onto them. The biggest patches
were attached to the wall before the grout pump came. At each hole, we filled it with grout,
and then, using a cordless drill, screwed on the patch with the elbow, and topped it off.
When the grout was set up enough not to slump very quickly, I replaced the elbows with the
plug patches and let it set up more. Here's
some photos taken part way through swapping the full elbows for patches. Because we didn't
have time to trowel the concrete flat where the joist shoes would go, the hardened concrete
needed to be ground out in several places, while in others there wasn't enough of it. The
grinding took about a week. I had considered to use the non-shrink grout that Hambro
recommended for use immediately under the garage post to fill in these places, but the
grout manufacturer says not to use it in applications where it would be less than an inch
thick. What I found to use in these places is ITW Philadelphia Resins'
Chockfast Gray. This is considerably more expensive than the Portland Cement based
Grout: ~$80/gal versus ~$16/50 lb. bag. However, it has the same properties for supporting
high loads, not shrinking and can be used at thicknesses down to 1/4". In addition, it
has the benefit of pouring about like wet paint when it's first mixed up, so I should be able
to support a joist shoe with a piece of 1/2" steel square stock ground to the proper length,
pour in the Chockfast and let it all set up. I haven't done this yet. The initial grinding
took about a week. I checked the height of all the joist shoes resting on concrete with the
laser level one night, and a few are about 1/4" higher than the two beams over the doorways
(which are exactly the same height), so there's a little more grinding of those in my future.
Next, I built the form for the pad under the post in the garage, and we drilled the pads under
the columns on either side of the front door and glued in the vertical rebar. Then, Steve and
I leveled the column pad box, wired in the cross bracing for the vertical rebar, and leveled
the cardboard tube forms for the underground 10' of those columns. We had those forms filled
by a concrete conveyor truck. I vibrated the pad form with the pencil vibrator and did the columns
with the Rebar Shaker. Just as the truck was cleaning up, one of the cardboard tubes gave
way and spilled all its concrete out the bottom.
Here's some photos and details of that situation. Here's how it looked when I stopped
working on it, just before the Thanksgiving holiday. I accompanied Raimona, Steve, & family
on their annual trip to spend Thanksgiving with my parents, and stayed to visit with my parents
when they returned.
- We weren't prepared for how messy it would be and how much time cleanup
- We should have had plastic placed everywhere along the base of the walls and
tarp over all the tools in the middle. Cleaning up the splatter took at least a person-week.
- We weren't willing to postpone the pour on account of the weather.
- This wasn't a problem so far as the wall was concerned, but the rained drops
messed with the smoothness of the surface were we filled in the last of the basement
floor in the stairwell.
- The pump truck operator said that he thought that I could be an entire lift behind
Steve, and the concrete wouldn't be too set up to vibrate.
- This wasn't the case. When I was about forty feet behind Steve and doing the
garage frost wall, the concrete was getting too thick to vibrate quickly. This got
me even further behind Steve.
- We didn't hire any help
- I now know that there should have been at least 5 people working that job: one placing,
two vibrating, one finishing the floor concrete, one running, fetching, straightening the
rebar angles and troweling the concrete flat where the joist shoes were, and one QCing the
concrete and watching things, making sure unexpected stuff didn't happen. Being too cheap
to hire anyone even to consult with us and tell us that we needed more help before our first
wall pour really bit us in the ass.
- We trusted the concrete company, and they behaved poorly.
- While we were discussing the order for the concrete, they told us that they usually
liked to deliver a slump of 5 for ICF walls and that they liked to send their trucks
every half hour. Sounding very confident, they said that they pour these kinds of things
every day, and that there wouldn't be any problem. Well, they may do lots of ICF walls, but
apparently not that many grid system ICF walls. Rastra corporation specifies a
minimum slump of 7, and that's what we ordered, with trucks to arrive every 40 minutes.
The first truck came 40 minutes late, but the rest of them came (every half hour it seemed)
timed as though that first truck had arrived on time. About half-way through the pour they
started delivering concrete with a slump of about 4, but they didn't tell us about it. Steve
placed about 50 feet of it, before he stopped and started asking what to do about it.
By then, I was working in the frost wall, falling further and further behind because of
the concrete having set up from my being behind in the fist place. I finished the frost wall
then switched to trying to get that concrete to go down, Steve got the drivers to add more
water to the concrete that was still in the trucks, and placed the rest of it. The pump
truck driver left us some dollops on top of the plywood on the joists we were using for
scaffolding, and then cleaned up and left. We spent the rest of the time until it hardened
trying to get the concrete to go down into the forms. Part way through this process, on the
recommendation of the pump truck driver, I switched from the Rebar Shaker head to a pencil
vibrator head and that put more energy into the concrete, getting it to go down a little better.
Steve later told me that the concrete truck drivers blamed us for ordering their product rather
than that of someone located closer to our job site. Needless to say, they won't have
any concerns about us ordering their product ever again.
I arranged for Seven Valley Construction to fill the upper part of the inside of the garage
frost wall with gravel (unsorted "crusher run") and to build a gravel ramp leading down from
there to the driveway while everyone was down with my parents. After Raimona, Steve & family
returned, I asked them about the results of that work, and they said that the quality of the
work was good, and the labor charge was about as expected, but the volume of gravel (and hence
the total expense) was a lot more than anticipated.
Well, that's it for this year. I'm once again hoping for a roof on it by Thanksgiving of
On to part (year) three.
Here's a link back.