Specifications 101: Choosing the Right Materials for the Job

Drawings show you where it goes. Specifications tell you what it is. Don’t install cardboard when you need concrete.

When you look at a set of blueprints, it is really easy to think you have all the information you need to build something. But blueprints only tell half the story. The drawings show anything measurable, like how many cubic yards of concrete are required in the foundation or the number of doors onto the patio. However, you also need written descriptions, known as specifications, to detail the materials, processes, and quality.

Without these written details, you might know you need a door, but you will not know the manufacturer, the material, or the type of glass required for that door.

The Core Concepts of Building Specifications

Before diving into specific projects, it helps to understand how building information is organized and what kinds of specifications exist. Here is the basic breakdown:

• Specifications provide critical information added to the architect’s or engineer’s drawings.
• Contractors study the specifications to determine the quality of products and installation methods.
• On large projects, specifications are generally bound together into a project manual, which provides an organizational framework for all the written documents.
• There are four ways a specification writer might identify product requirements: descriptive, performance, reference standard, and proprietary.
• Descriptive specifications provide product details without specifically mentioning a brand name.
• Performance specifications identify the ends to be achieved, but not how the ends are achieved.
• Reference specifications identify a required standard such as ASTM, State of New York, Federal, and so on.
• Proprietary specifications identify the desired product by manufacturer, brand name, model, and so forth.
• The Construction Specifications Institute (CSI) created MasterFormat to organize construction requirements in a clear and consistent form.
• MasterFormat is organized into numbered Divisions that represent categories of materials, products, and systems.
• For example, Division 03 is Concrete.
• Division 09 is Finishes.
• Conflicts can easily happen when information differs between the drawings and the specifications.
• The best way to avoid conflicts is to remember a simple industry saying: say it once, and say it in the right place.

Now, let’s look at how to actually use these concepts out in the real world. Whether you are building a tiny home or fixing up a rental, picking the right type of specification method can save you time, money, and massive headaches.

Disclaimer: The information provided in this article is for educational and informational purposes only and does not constitute professional construction, contracting, or business advice. This content is derived from personal academic notes and coursework in construction management. Always consult with licensed professionals and verify local building codes before applying any concepts to real-world projects. The author assumes no liability for any errors, omissions, or outcomes resulting from the use of this information.

🏗️ 1-Man Tiny Home: Focusing on Results

Concept: Performance Specifications

When you are building a tiny home entirely by yourself, your budget and flexibility are huge factors. You don’t always need the fanciest name-brand materials. What you really need is for the materials to do their specific job well. This is where performance specifications come in handy. As a reminder, performance specifications are a method of specifying that identifies the ends to be achieved, not how the ends are achieved.

Solo Tip: Don’t buy “Brand X” insulation just because you saw it on a home improvement blog. Buy “R-15 value” insulation. Specify the performance (the warmth and insulation value), not the brand. For example, a specification might simply state that an exhaust fan needs a capacity of 500 CFM. By focusing on the performance requirement instead of a specific brand, you can shop around at different hardware stores and buy whichever brand is on sale that week, as long as it meets that 500 CFM or R-15 rule. It keeps your budget low while keeping your quality exactly where it needs to be.

🏚️ Single-Family Fixer: Preserving the Charm

Concept: Proprietary Specifications

Flipping or restoring a single-family home — especially an older historic one — requires a totally different approach. If you are patching drywall, matching historic trim, or touching up exterior paint, close enough isn’t good enough. You need an exact match so the repair blends right in. This is the perfect time to use proprietary specifications. Proprietary specifications identify the desired product by manufacturer, brand name, model, and so forth.

Solo Tip: When patching old houses, use proprietary specs to ensure the new paint or trim matches the old exactly. Instead of just writing down that you need “white floor tile,” a proprietary specification would dictate that the floor tiles need to be “Contempo” manufactured by Kentile Corp. If the original house used a very specific custom-milled baseboard from a local lumberyard, your project plan needs to name that exact lumberyard and the specific product number. This guarantees that your contractors won’t show up with a generic replacement that ruins the historic look of the house.

🏠 House Hack Fixer: Built to Last

Concept: Reference Standards

A house hack is when you buy a multi-unit property, live in one unit, and rent out the others to cover the mortgage. Because you are dealing with tenants, the materials you use need to be exceptionally tough. Standard residential-grade stuff will get destroyed in a year. You need materials that can take a beating, which means you should rely on reference standards. Reference standards are a method of specifying that identifies a required standard, such as ASTM, state, or federal.

Solo Tip: For rental units, buy materials that meet strict “ASTM” durability standards (commercial grade) rather than just standard residential grade. For example, a specification for Portland cement might require that it conforms to ASTM C150. If you are putting down laminate flooring in a high-traffic rental, you don’t just want any flooring. You want flooring that meets a specific commercial abrasion standard. By using reference standards, you weed out the cheap, weak materials and ensure you are installing products that will survive multiple tenant turnovers.

Conclusion

Whether you are managing a massive commercial site or just fixing up a duplex on the weekends, knowing how to specify your materials is an absolute game changer. The drawings might show you where a wall goes, but the specifications and the drawings work together to provide the information contractors need in order to price and build a project. By understanding the difference between performance, proprietary, and reference specifications, you can control your budget, preserve your property’s charm, and ensure your work lasts a lifetime.

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