Stucco home made formula

[Guest]

In my area, stucco is rarely used as an exterior finish in new home construction, and none of the local suppliers offer it. I could probably find it if I searched extensively and traveled to pick it up.

I was wondering if it can be made of found materials. The local suppliers all have a large variety of plasters, cements, bonders, and dyes. What is stucco, and can I make it from scratch? I only have about 4 square feet to do on this particular project so the efficiency of mixing my own from found materials would match travelling far and wide to find it.

[Guest]

Re: Stucco home made formula

Hi Thomas,

You've asked a question that requires my pulling out my Northwest Wall & Ceilings Bureau recipe book. I'll give you some recipe choices and then some rules to work with.

Mix #1 Basecoat: 1 part portland cement, 1 part masonry cement, 3-1/2 - 4-1/2 parts sand, fibers per manufacturer's recommendations.

Mix #2 Basecoat: 1 part portland cement, 1/4 - 1/2 part lime, 3 - 4 parts sand, fibers per manufacturer's recommendations.

Mix #3 Basecoat: 1 part 1-P portland cement, 1 part masonry cement, 3-1/2 - 4-1/2 parts sand, fibers per manufacturer's recommendations.

Mix #4 Basecoat: 1 part plastic cement, 3-1/2 - 4-1/2 parts sand, fibers per manufacturer's recommendations.

Mix #5 Basecoat: 1 part portland cement, 1 part plastic cement, 3-1/2 - 4-1/2 parts sand, fibers per manufacturer's recommendations.

Job-site finish coat: 1 part white portland cement(or regular portland cement), 1-2 parts lime, 3 parts sand. (Note: If used, add manufactured coloring compounds to job-site stucco finish mix per manufacturer's recommendations.)

Manufactured finish coat: Mix and apply per manufacturer's recommendations.

If you're doing repair work, you'll need to use bonding agents. These will need to conform to ASTM C932 and be nonoxidizing, non-crystalizing, non-re-emulsifiable. Apply per manufacturer's recommendations.

PLASTER SPECS

a. Basecoat - Portland Cement: ASTM C 150 Type I or Type I/II; Masonry Cement: ASTM C 91 Type I or Type I/II; 1P Portland Cement: ASTM C 595; Manufactured Basecoat

b. Hydrated Lime - ASTM C 206 Type S

c. Stucco Finish - White Portland Cement ASTM 150 Type I or Type I/II; Regular Portland Cement ASTM 150 Type I or Type I/II; Manufactured stucco finish

AGGREGATE

a. Basecoat sand - ASTM C144 or C897; natural or manufactured; washed and free of deleterious materials; locally available sand that approximates ASTM C144 or C897 when past performance has shown it to be suitable.

b. Finish coat sand - ASTM C897; Natural or manufactured; freshwater washed and free of deleteriious materials; locally available sand that approximates ASTM C144 or C897 when past performance has shown it to be suitable.

WATER

Potable, clean, free from impurities.

ADMIXTURES

Note: No household-type detergents or chlorides, only those manufactured specifically for use in a stucco mix.

a. Fibers - 1/2-inch long, ASTM C 1116 (Recommended as part of basic basecoat mix, but never use in finish coat.); Polypropylene, nylon or alkali-resistant glass fibers; use only types manufactured specifically for a stucco basedoat and per manufacturer's recommendations.

B. Air-entraining admixtures - ASTM C 260 consistent with manufacturer's specs.

c. Water-reducing admixtures - ASTM C494, Type A used consistent with manufacturer's specs.

d. Accelerating admixtures - ASTM C494, Type C and E; must be non-chloride or chloride with rust inhibitors; used consistent with manufacturer's specs.

COLORING COMPOUNDS

a. Prepackaged colors - (Recommended over b. when color is used)ASTM C 979; only those manufactured for job-site stucco finish; mix with finish coat according to manufacturer's specs.

b. Raw color pigments - ASTM C979; natural or synthetic iron oxides; variation in uniformity of color will be normal.

MIX PROPORTIONING RULES

- Proportions are parts by volume for basecoat and job-site stucc finish.

- Use standard measuring materials and know volumes for all materials.

- Sequential batches to be proportionally alike.

- All mixing in a mechanical mixer.

- Continue to mix for 3-5 minutes after all ingredients have been added.

- Add fibers 2-3 minutes before applying the basecoat.

- Factory prepared stucco finish per manufacturer's recommendations.

- Admixtures per manufacturer's recommendations.

- Cement materials based on full bag increments.

- Shovel count cann be used for measureing sand if standardized first.

- Keep water to a minimum, use only enough to produce suitably plastic cementitious material.

- Sequence of materials: (1) water (2) half of sand (3) all of the cement and/or lime (4) balance of sand (5)water for workability.

- Brown coat may contain the higher volume of sand.

- Sand per sum of cementitious material.

- For mix no. 1, 3, 4 and 5, volume of sand in first coat shal be the same or less than volume in second(brown) coat, not to exceed 4 parts of sand per sum of cementitious materials.

- For mix no. 2, volume of sand in first coat shall be the same or less than the volume of sand in the second (brown) coat, not to exceed 3-1/2 parts of sand per sum of cementitious materials.

- Amount of fibers always per manufacturer's recommendations.

Whew! That was a chore. Hope this provides you with what you are looking for. When you decide on a mix make sure you only use that mix throughout. Don't try to intermix different recipes of basecoat material between the scratch and brown coats.

ONE TEAM - ONE FIGHT!!!

Mike O'Handley
[email protected]

[Guest]

Re: Stucco home made formula

Tom:
Lumber yards and hardware stores carry a product called Mixquick (ther are also other brand names). It is already formulated for you. It comes in 90 pound sacks as I remember. They make several different mixes so be sure you get "stucco mix" and not something else like "mortar mix".

[Guest]

Re: Stucco home made formula

Thank you both, that is very helpful!