Last year we used dish soap and a car brush with very good results. Sadly, after cleaning only as high as I could reach from a 12’ ladder, time got away from me, and the remainder of the dome took another year of outdoor exposure and grime.
This car brush method took a good bit of elbow grease, so to reduce my pain issues, I challenged myself to get cleaning results as good as last year, but with less muscle fatigue – and to finish the job.
After some discussion, research and reliance on our past residential scrub-down experience, we opted to use a pressure washer – with great care.
The Monolithic Airform is incredibly strong and tough to tear. However, the material can easily be cut with a blade, and it can certainly be punctured with sharp or high pressured material, including nozzled, high-pressure water.
There was minimal set-up for this excursion beyond rounding up the required materials: extension ladder, soap, goggles, garden variety pump pressure sprayer, water and hoses, electrical source and cords, 200’ of 300 lb test rope, metal ground stakes, some metal rings and clips and a power washer. We also opted for a hydraulic boom lift to get me and equipment to the top of the dome safely.
You might find the following info valuable from our experimentation and experience as you prepare and wash your Monolithic Airform;
1) Pad your ladder where it contacts the dome to avoid denting the underlying foam.
2) Pad the leading edges of the boom lift basket and any heavy handled tools with foam pipe insulation, available at large hardware stores. Foam pipe insulation is similar to flotation noodles used for recreational swimming. Taping the foam in place saves a lot of re-placement of slipped and dropped foam.
3) My ladder of choice was a 30’ extension ladder, but a 20’ would probably have done just as well and been less heavy. This particular older, heavy ladder also had wide outrigger-type arms for support at its top end. A metal stake or two were driven to keep the base of the extension ladder from sliding away from the dome while I was aloft. Beware of this stake, as both my wife and I were bitten.
4) A point to remember: gravity works even when you’re not paying attention. I neglected this fact for a fleeting moment while experimenting on how to best move the ladder. It cost me an ER visit and five sutures in my arm.
5) Once back home, I decided to let physics work for me and that found moving the extension ladder was easily accomplished by wetting and soaping the Airform surface, lifting the ladder base so the outrigger arms were all that was touching the Airform, and then tilting the length of the ladder in the direction I wanted it to travel. With a little practice, relocating became almost effortless.
Our soap mix
Based on some experimentation our preferred soap mix was:
1 gallon of water
1 + ½ good squeezes of liquid dish soap with bleach substitute
1/5 measuring scoop (provided in product) of powdered and dissolved oxy-type general stain removing laundry product containing sodium carbonate and/or sodium percarbonate.
Be sure to dissolve the powder inside your hand-held pressure sprayer to avoid clogging the sprayer nozzle. Adding the soap to the water (instead of the water to the soap) inside the sprayer tank kept soap bubbles minimized.
Always wear goggles when mixing your soap, spraying your soap and spraying with your pressure washer. Sutures are a pain in the pride, but eyes are nearly priceless.
The 200’ of nylon rope was cut in half. A 2" metal ring was passed onto both ropes until it was in the middle of each rope. About 6" of loop made in the middle of each rope was tied in an overhand knot to secure the 4 strands of 49’ lengths of rope.
The ring is secured in the loops just beyond the knot. This giant X spanning 49’ in 4 directions was centered on top of our (50’ x 21’) dome, and each strand was staked at least 12” into the ground. Upside-down recycled produce cans on top of the metal stakes prevented further leg injuries.
Our pressure washer of choice was a light duty 1600 psi. We have used the Karcher brand with excellent wand control and satisfying results. These are lightweight units with all the heft needed to remove two years of grime on our dome, yet with enough finesse not to overpower and cut into the Airform. And I didn’t feel beat after working for a few hours.
With our supplies gathered, helpers and good weather, we finished cleaning our 3600’ square Airform in about 15 hours. My estimated costs included: pressure washer $125, extra help to halve the work time $200, hydraulic boom lift rental for 3 days $325, liquid dish soap with bleach substitute $2, Oxy-type stain remover $3, ER visit cost pending, wife’s chance to re-remind me about being safe – priceless!
Happy Airform cleaning! It sure beats cleaning windows, and it’s really tough to beat the view from high atop a clean Monolithic Dome Airform.
Editor’s Note: For more information on Airform cleaning please review
Note: Maddy and Chris Ecker, the owners of a Monolithic Dome home in Galax, Virginia, often share their Monolithic experiences with us.