1 - Quality of Workmanship and Stds.pdf

Quality Workmanship

Standards on Fort Leavenworth, Kansas

Historic Buildings

Table of Contents

Purpose of the Standards

Introduction. How the Standards Work

Section I. Quality Masonry Standards

Acceptable Practices

Unacceptable Practice

Purpose of the

Standards

1. To provide a clear, visual standard to contractors, DPW and COE inspectors on all masonry projects on Historic Buildings at Fort Leavenworth, Kansas.

2. By providing a standard, each worker and inspector can understand what level of quality is expected before the project begins.

3. During the construction phase, the inspector(s) will use the standard as a visual guide for identifying acceptable and unacceptable workmanship. Therefore, it also becomes a continuous training tool for contractor(s) and inspector(s).

4. Increasing the level of quality produces:

A longer-lasting product

A work of craftsmanship

A savings of repair and replacement dollars

Introduction How the Standards Work

To Contractors and Inspectors:

These standards shall be the guide for all work and inspections on historic buildings at Fort Leavenworth, Kansas.

Historic buildings require strict construction practices and a high degree of quality work.

By not following these standards and/or identified by the Government Representative or representative, will require the contractor to remove the unacceptable work and replace it, at contractor's cost, with the acceptable, quality craftsmanship described in these standards.

These standards will help the contractor and the inspector to clearly identify acceptable craftsmanship, as well as, poor workmanship on historic projects. Following these acceptable practices preserves the existing historical material, prolongs the life of a new repair and restoration work, delivers a higher quality product that will last, and save future funding dollars.

Section I.

Acceptable Masonry Practices

Section I. Quality Masonry Standards

Acceptable Practices

Quality Assurance

Original Historic Brick and Stone Materials

Tuck-pointing Techniques

Matching Brick and Stone

Mortar Application Techniques

Mock-Ups Requirements

Use of Hand Tools/Power Equipment

Mortar Mix Quality

Clean-Up and Finish Work

Unacceptable Practices

Working with Original Historic Materials

Poor Mortar Application Techniques

Poor Mortar Mixing Techniques

Clean-Up and Finish Work

What is Quality Masonry Restoration?

Quality is key to masonry restoration and is defined as a "degree or grade of excellence" according to The American Heritage Dictionary. However, quality is still not clearly defined but we all know it when we see it.

However, with these visual standards, quality can be identified, at least, in regards to masonry restoration. This will help improve the life span of these historic properties.

Tuck-pointing

Tuck-pointing is the re-pointing of the deteriorated mortar joints in an existing masonry wall.

Once mortar joints are ground out to desired depth, we recommend a minimum of 1/2" deep, dust out joints with brush to remove dust particles. Then, rinse joint with water hose to make it dust-free and ensure proper bonding.

Proceed with tuck-pointing and look for the following quality standards:

No air bubbles in mortar in joint

No openings in mortar in joint

Mortar is flush with brick (or as specified)

No mortar is on the face of the brick, that is, smeared

No dust is on edge of brick reducing proper bonding

Allow time for joints to dry. If the mortar turns white and smears the brick, it is too dry. If mortar begins to turn white, misting is needed and color of joint.

When to re-tuck-point

When a lot of mortar falls out and the joint is already a 1/4".

Appearance is poor and you need to dress it up.

Tuck-point 100% solid when more than 50% of the joints are deteriorated. Recommend using type N mortar.

Patching Masonry

Patching masonry is repairing deteriorated/spalled masonry such as concrete, brick, stone and terra cotta to ensure it being weather-tight and/or to repair the masonry so it looks better and is not a safety hazard.

One product in particular that is superior is Jahn Restoration Mortars manufactured by Cathedral Stone Products, Inc. installed by trained craftspeople that are certified to install Jahn products.

When patching masonry with any material, the applicator will generally follow these steps:

Remove all loose materials in patched area

Square off edges to be patched

Create a minimum of a 1/2" deep for patched area

Dust out area to remove dust and dirt

Apply primer with brush to area

Apply paint/rust inhibitor to exposed rebar

Apply patching material with margin trowel

Apply straight edge to material and smooth out to ensure material is flush with adjacent masonry surfaces

Mist patched area three times a day for three consecutive days

Look for these performance standards:

Material is flush/even

No dents or holes in patch

No smear on outside of patch

Area is damp

Texture matches existing

Knowing when to patch masonry

Where loose masonry is severely cracking, spalling, rupturing, or popping off.

When you have water damage or leaks inside.

When the appearance is very noticeable.

When the deterioration could cause damage to property and/or persons.

Cleaning Masonry

There are several methods of cleaning masonry. Knowing which method is vital to restoring/preserving existing masonry. Most masonry can be cleaned using only water at varying pressures (psi). However, some form of chemical cleaning and/or sandblasting may be necessary when your masonry has any of the following problems;

deep rust stains, chemical residue, efflorescence, graffiti, paint, and years of neglect. Determine what chemical and psi will cut existing dirt/stains. Always do a sample when chemical cleaning masonry and get data sheets.

Historical Preservation

Do not ever sandblast a historical site unless you do not mind losing its historical heritage and/or recognition.

Always use a low psi between 300-1000 when cleaning masonry on a historical site.

Always use a properly mixed historical mortar consisting of the following:

1. 6 parts sand or matching aggregates

2. 1/5 part Portland cement

3. 2 parts hydrated lime

4. 5 gallons of water or until mortar can be rolled into a ball and provides a thumbprint

Screws and Bolts - Use lag bolts and washers where there may be structural concerns.

Use Detailing from DPW - the DPW will supply details for porch elements where there are several kinds of mismatched wood trim, columns, bases, spindles, and railings.

Stone brick face is free from unwanted mortar and has a clean look and feel.

Mortar joints are clean, smooth, uniform, within the spaces between the stones, and consistent with color. Matching color of existing historic mortar.

Brick is free from unwanted mortar and has a clean look and feel.

Masonry mock-ups or sample tuck point areas may be required before starting work. Construct 3' x 5' units. Mortar must be completely dry before inspection and final acceptance before work begins.

Structural members shall not have broken parts or splitting through members.

Unacceptable Practices

Mortar is smeared or left across stone or brick face.

Applying the wrong color of mortar, which should match the existing mortar.

Poor color selection of brick.

Unacceptable Masonry Practices - Brick

Overly wide tuck-pointing joints.

Brick was destroyed by pneumatic tools and wider the space.

Excessively wide Tuck-pointing Joint.