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Ferrocement Garage - page seven
Cultural & Ecological designing
ferrocement garage - front view ferrocement garage - rear quarter view

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Here's where you'll find some of the details not covered in the previous photo-essay pages, such as what tools I used, how much stuff cost, how long it took, details on materials and methods, some major and minor mistakes I learned from, and other semi-random project information.

I may add to this page from time to time as I recall additional details. If you have a question or want more information about some aspect of the project, contact me and I'll add the answer and/or info to this page.

Except for the metal roofing (which was delivered), all the materials were brought to the site by 'Auntie Spud' (my 1988 Ford Festiva), which I also refer to fondly as 'my quarter-ton pickup'.

[Auntie Spud with load of 20 foot long rebar] Twenty-foot rebar? No problem (not with a custom rack extender made from salvaged wood, anyhow)! Shoulda seen the look on the guy's face at the building supply place, though...until he saw the rack extender...
Seven hundred pounds of mortar sand? Problem...handling got pretty squirrely over 45 mph, and the rear suspension was about bottomed out. After that first load I kept it down to around 1/4 ton (500 lbs.) and problem! Shoulda seen the looks on folks' faces at the scalehouse though...first time, anyhow...they got used to it. [Auntie Spud with first load of mortar sand (700 lb.!)]
What stuff cost - and de facto materials list:

By far the largest cash outlays were for the metal roofing, roof framing wood and related hardware, and bobcat work/cinder/hauling for building site preparation. The materials for the ferrocement part of the building were relatively cheap.

  • For armature: three-eighths inch rebar in 20 ft. lengths was $2.69 per piece; I bought two dozen, so roughly $65 (about half of which was rendered surplus and available for future projects when I ditched my ferrocement roof idea). Nine gauge galvanized wire was about $12 for a ten pound roll and I used not quite three rolls - $36. A 150-ft. long, six foot wide roll of one inch galvanized hexagonal mesh was about $90. That was enough to put three layers on the walls. Expanded metal lath, enough to put a layer of that on top of the mesh and on the front arch, was around $120. Tie wire - $20 or so. So roughly $320 for all the armature materials.
  • For plaster: type II-III portland cement at about $9 a 90 lb. bag - I used about six bags, $54. Mortar sand - $34.50 a ton. I hauled six loads averaging about 1/4 ton each, so roughly 1 1/2 tons for a total of about $52. Water - free. So materials cost for all the plaster used in the building was around $120 dollars.
  • Metal roofing and all necessary screws cost almost exactly $600. That includes both roof and door covering and local delivery (which was included at no extra charge for purchases over $500). There was no extra charge to have the pieces cut to whatever different lengths I wanted. I figured out in advance what lengths I needed, so that the only cutting I had to do was trimming the front and rear of the roof and the top of the rear door to shape and cutting one piece in half lengthwise to complete the front door covering.
  • For roof framing wood, framing brackets, bolts, screws, ready-mix concrete (at $4 a bag), Odjob mixer, rebar and a few other odds and ends I have receipts totalling roughly $550. The 2x4 material for the stringers and trusses totalled $105 and the 1x3 clear straight-grain material for the battens was $108.
  • The custom welded door frames cost $170 for all three pieces. There was another $50 or so in related hardware - hinges, drop bolts, fasteners.
  • The bobcat work, cinder material and cinder hauling cost $370.
  • Renting the nibbler and generator to trim the roofing metal cost $43 for a day's use.
Throwing in a fistful or two of dollars for other odds and ends, the building and site preparation total cost was around $2200 dollars. The building interior is somewhere in the neighborhood of 230 'round feet', giving a 'per round foot' cost of about $9.50/rnd. ft.


Most of the work was done using hand tools - I used only two power tools on the building. One was a Makita cordless drill, for driving wood and roofing screws and drilling assorted holes, such as for bolts in the ferrocement, wood framing, and metal brackets. I bought a 12v charger for the drill batteries, so I could charge them off my car battery (it plugs right into the cigarette lighter socket). TIP: to drill ferrocement, buy the impact-drill rated masonry bits, even if you aren't using an impact drill. They work, they last, they're worth the extra money. The ones that aren't rated for impact drills break very easily, especially if you hit much in the way of metal - which you're bound to do in ferrocement.

The other power tool was a Hitachi electric sheet metal nibbler. This I rented, along with a little Honda 1000 generator to power it, after I had everything in place, marked and ready to cut or trim. This is a very slick tool. I couldn't rent it for less than a day, but I don't think it took me more than forty-five minutes of actual generator run time to trim the front and rear roof edges and rear door top edge and cut the front door pieces to width. TIP: cutting more than one thickness of roofing with this tool is supposedly a no-no that will most likely break it. I didn't want to risk breaking a $300+ rental tool, so I had to partially unscrew my fully screwed down roofing near the edges of the roof, and then prop it apart an inch or two (with a scrap wood wedge) so I could cut one thickness at a time where pieces overlapped. Avoid this by cutting before installing - if that's not practical, avoid screwing down overlapping areas that will need to be trimmed so they can be propped apart a couple inches to clear the nibbler anvil and cut one at a time.

Using these two power tools, I saved quite a bit of time, but they were not absolutely necessary. I could have done all the drilling and the roof trimming by hand. Hand drills and braces are still relatively easy to find. There are hand-operated sheet metal nibblers, though I have yet to find a source for sturdy ones that can cut roofing metal - any info on where to find one is welcome. Tin snips work poorly for cutting corrugated metal roofing, as do hacksaw blades in the one-handed blade holders. I haven't yet tried a masonry-type carbide rod saw on metal roofing, but I am pretty sure it would work better than tin snips or hacksaw blades. What to use for a holder would be the tricky part.

Primary hand tools used consisted of the following:

  • An 'Odjob' mixing drum for concrete and mortar mixing. This is a great device, made of recycled plastic no less. Throw in the ingredients, roll it back and forth for a minute or so and your concrete or mortar is nicely mixed. Using one well takes a bit of practice, both in finding a safe and effective body position for rolling it and in getting a feel for how the mix is doing by the sound and feel of the rolling mixer.
  • Stucco trowels for plastering. I found inexpensive steel stucco trowels with nice fat plastic handles. I bought several and trimmed the square corners round using tin snips and a metal file. I cut a different corner radius on each one, mostly to see what would work best for different parts of the wall (flat areas vs. inside corners, etc.). Mostly I used the same trowel the whole time, with only slightly rounded corners. On the tightest inside corner I used one that I had rounded off so much that it was like a small pool float (but much cheaper...). TIP: Unless you have really tiny hands, buy only trowels with nice fat handles - you will have a much more solid grip and far less hand/arm fatigue than with too small a handle.
  • Smallish masonry trowel (the diamond-shaped kind) for plastering. I used this mostly to load wet plaster onto or trim it off of the stucco trowel, and for detail work around the hinges and other tight or small spots.
  • Diagonal wire cutters and linesman's pliers - good quality sturdy ones - there is a lot of cutting and twisting and bending of wire involved.
  • Rebar cutter/bender - rented for a day twice during the course of the project. I could bend broad curves easily enough by hand in 3/8" rebar, and make the occasional cut here and there with a hacksaw. The cutter/bender was really worth it, though, when I was set up to make a whole bunch of cuts and/or tight bends at once.
  • Square-headed, short-handled plastic nylon bristle brush - for rinsing out the Odjob, cleaning trowels and hod, splashing water on the walls, roughing up the edge of a batch of plaster as it sets up. The ones shaped like an iron work well too.
  • Sponge - medium utility size, synthetic - for smoothing joints between plaster batches, wetting down small areas of wall, wet-sanding rough spots in partially cured plaster.
  • Shovel - for loading and unloading mortar sand from whatever conveyance you are transporting it to the work site in.
  • Mason's string line - for lining up tops of vertical wall rebar, checking trueness of roof stringers, etc.
  • Water level - for measuring and setting roof pitch, leveling hinges with each other, leveling tops of door frames, and all kinds of other leveling or height-difference measuring tasks that aren't suitable for a builder's level. I made my own water level very simply and cheaply by buying 50 ft. of flexible clear plastic tubing and putting water in it. TIP: forget any instructions or diagrams you may have seen involving making a water level using short pieces of clear tubing (with hose hardware and clamps and other complicated stuff) that connect to either end of a garden hose. Garden hoses are way larger and heavier than necessary, and there's no way to be sure you've got all the bubbles out. Seven-sixteenths or even three-eighths inch inside diameter flexible clear plastic tubing works just fine and is much lighter and easier to handle - and, you can be sure you've got all the bubbles out! Rig the ends of the tubing with some easy way to hang them both up together on whatever is handy (rebar, tree, car mirror, gate post, tent pole, etc.) - use bungee cord, wire twist ties, rubber bands, string, whatever works for you. This helps avoid absent-mindedly setting one or both ends down on the ground and having the water run out while you're busy doing something else...
  • Builder's level - I had only a borrowed 2-foot level for this project, which in combination with the water level was all I needed.
Other equipment (not really 'tools', but really necessary):
  • Gloves - tough rubberized ones (usually vinyl, actually), for all work involving cement - mixing/pouring concrete for footings, mixing/applying plaster on walls, plastering edges of doorways and walls, cleaning the Odjob, trowels and hod, sponge-smoothing seams between plaster batches. Sturdy leather ones for work with armature materials - handling big rolls of wire mesh, bending rebar, moving sheets of lath around. For the fine motor work of tying the mesh layers together with 20-gauge wire, it is almost necessary (and certainly faster and less awkward) to work with bare hands, though the cotton garden gloves partially coated with thin grippy rubber might be OK for some of that work.
  • One-gallon plastic utility buckets - for measuring plaster ingredients, rinsing out the Odjob, cleaning trowels and hod, keeping a sponge and brush wet in.
  • Ladder - for preparing upper armature sections, plastering upper wall sections, building the roof, and taking pictures looking down on the building in progress. For this project I made do with a borrowed, beat up, barely six foot flimsy painter's ladder. It helped that I'm six-foot-three - otherwise I might have had to get a taller ladder...
  • Hods - what the plaster is placed on when it's dumped out of the Odjob mixer. Pieces of salvaged/scrap plywood work fine. I had a big one that could hold a whole batch, and a couple smaller ones that I could plop some plaster on to take up the ladder and set on the paint tray (for working on the higher parts of the wall and above the doors). TIP: wet wood hods down before using so they don't suck the moisture out of your plaster.
  • Blue plastic tarp - for keeping the sand pile under cover. If it rains on your uncovered sand pile, the amount of water you've learned to add to dry sand and cement for a 'perfect' plaster mix won't work any more and you'll have to figure it out all over again, possibly wasting materials and certainly wasting time in the process. Then the sand will start to dry out, and it'll change again...and again...just keep it covered. Do not use just a tarp laid over them to cover cement/concrete bags!
  • Salvaged/scrap metal roofing (and lumber and/or masonry blocks to prop it up/hold it down) - for keeping cement and/or concrete mix under cover and dry on the work site, if you don't already have a roof on the building or very nearby, which I didn't. Do not use a tarp for this, unless it's supported off the bags by a frame of some kind - moisture from condensation due to lack of air circulation will mess with your cement!
And last - but not least:

[Micro-catchment setup for work site water supply] Garbage can - to hold water for scooping out of when cleaning Odjob mixer and plastering tools. I had no water on the site other than what I hauled in jugs and what fell from the sky. I set up a micro-catchment system using salvaged metal roofing, trees, sticks, bungee cords and a trash can. It filled up before I got started plastering, but it was a fairly dry spell while I was doing the plastering and the garbage can was replenished from hauled-in jugs more often than from rainfall.

Time and process:

The total project was spread over about three months. I was not working on it full-time, and my work schedule varied quite a bit from week to week and day to day. At present I estimate I worked about 2/3 of full time on the project, including materials runs, design and brainstorming time, and direct project work starting with setting up the armature and ending with finishing the doors. That means about two months full-time equivalent.

My girlfriend Ayars helped with building the armature, but I didn't keep track of her hours. I had two people helping to plaster part of the inside for roughly three days. They were new to the work, and by their last day the two of them together were working about as fast as me alone.

Most of the work could be done equally well in little bits or in long stretches. Plastering required a minimum time commitment, namely to complete at least one batch. On full days I did four batches; I might have done five batches in a day once or twice. Three was more typical, depending on what else needed to get done that day.

Once I had the plastering down, I could put a full batch on the outside, which was a bit wobbly until it set up, in about 45 minutes. Working time for a batch was an hour, maybe an hour and a quarter maximum, then it would start to stiffen and/or get dry. My first half dozen or so batches were barely on in time - after that it was usually no problem, unless it was really hot, sunny and windy and I forgot to (or couldn't, depending on where I was working) keep the batch in the shade and the mortar stiffened quicker. Working tight corners, especially inside corners, and details like around the hinges also slowed me down some.

Once the outside was done, the structure was rigid, and the inside surface was nice and rough and took plaster quicker and easier than the wobbly outside. Also, the ground inside was all clear and level, whereas some parts of the outside were uneven, next to a steep slope, close to trees and so on, which increased the time it took me to set up and apply a batch.

Beside application time, there was mixing time (about 10-15 minutes once I had it down) and cleanup time (about 10 minutes once I had it down). My routine was to mix a batch, dump it on the big hod, and let it sit and slump while I cleaned out the Odjob. Then I'd apply the batch, clean the tools and hod(s), and repeat. I also needed to keep an eye on recently applied batches - before they had set up too much, but after they had set up enough, I needed to rough up the feathered edges and/or sponge-sand smooth the overlap with an older batch.

About the images in this document:

Most all of the images presented here were taken with single-use ('throw-away') fujifilm cameras with developing via Wal-Mart processing service. Although I scanned the master images at 300 dpi with a good-quality scanner, and most were tweaked to varying degrees using image editing software, the mediocre quality of the original prints is fairly evident.

A few of the images - mostly the close-ups - were taken with my venerable Pentax ME Super SLR with CPC 28-70 mm zoom lens with macro capability, using Kodak 200 speed slide (transparency) film. These were scanned using a Nikon CoolScan slide/transparency scanner. The result is of course much clearer, crisper, higher quality images.

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