Illustration of a substitution request form

Architects spend their entire careers thinking, reading, and wondering about materials. Over time, we develop very clear favorites. The choices are based on many factors — durability, aesthetics, ease of use, compatibility, availability, and cost. After a few years, our construction specifications have been carefully crafted and revised, and details have been painstakingly developed with every little thing considered. Naturally, the phrase “substitution request” is not a favorite.

It conjures up images of cheap imitations, revised detailing and — most disturbing of all — liability. Who wants to be the architect who approved the Chinese drywall over the USG, or the 90s-era EIFS instead of real stucco? The lawsuits never end.

So, if substitutions are so onerous to architects (and often to owners), why is there a section of most construction contracts devoted expressly to making them possible? The answer is: money, mostly.

Reasons for valid substitution requests

There are a few reasons a contractor might propose a substitution and an architect and owner might accept them.

Value engineering

This is a fancy term for cost-cutting. A result of a post-war collision of materials shortages and improved engineering calculations, proper value engineering is a method of identifying a less expensive way to accomplish the same results.

In practice, it’s often just a term applied to substitution with a cheaper product. This isn’t necessarily a bad thing, but you should expect some pushback from the architect — because they’re the ones who accept all the liability for this product.

Material scarcity

Occasionally supply chains get disrupted (see aforementioned Chinese drywall example) and substitutions have to be made to complete the project and keep the schedule.

Often, there are perfectly good substitutions — one hardwood is often as good as another — and the substitution is an easy one to make.

Availability of other materials

A contractor’s yard is often full of old materials — some purchased by mistake, some attic stock, and some extra. Occasionally, this means they can offer this material to an owner at a discount.

New products on the market

Specs tend to get used over and over and are often outdated. If a new, improved product is available, a substitution for that material might be in order. There are even times when a specified material is so out of date that it’s no longer available at all.

Why a substitution request matters

The burden of proof is on the contractor

Very few commercial projects are completed without a substitution, yet the process is not clearly spelled out in the AIA201 Contract for Construction, nor does the AIA publish a form specifically for substitution requests. In fact, the only mention of substitutions in the entire AIA contract is this:

“3.4.2 Except in the case of minor changes in the Work approved by the Architect in accordance with Section 3.12.8 or ordered by the Architect in accordance with Section 7.4, the Contractor may make substitutions only with the consent of the Owner, after evaluation by the Architect and in accordance with a Change Order or Construction Change Directive.”

So, in order to prevent disputes and ensure payment, the Request for Substitution needs to be extremely well-documented. Remember, by suggesting a change in material or assembly, you’re essentially changing the design. So, you need to think like an architect, which means being thorough to the point of fussy. 

Substitution requests can prevent payment disputes

Clarity is key. In submitting a Request for Substitution, you are wading into the design process and, in doing so, taking on a bit of liability. It’s important that the request is crystal clear about what is being proposed, the work it affects, any changes to the contract time and any changes it might make to the overall project’s operation or looks. Disputes arise when expectations are not clearly communicated.

If the Request for Substitution doesn’t accurately reflect the work, there’s a chance you won’t get paid for it. The work done has to match the work in the contract exactly to help avoid payment disputes, and that begins with the request. 

Make sure you understand what you’re proposing, and that you can accomplish the intent of the contract with the product you’re submitting. And no matter what, do not start the effected portion of the work until the substitution has been accepted and documented by issuance of a change order, construction change directive, or architect’s supplemental instructions.

These are the only methods of revising the contract to reflect the substitution — and if it isn’t in the contract, you can’t get paid for it.

Submitting a substitution request

The two key things to keep in mind when submitting a substitution request are “consent of the owner” and “evaluation by the architect.” 

Those are the criteria, so to meet them, your request for substitution has to make two cases — it has to convince the architect that it’s an acceptable replacement for the specified item, and it has to convince the owner that it’ll save them some money.

Substitution request form

Contractors often issue a change order request, but substitutions actually have their own process. Though it’s possible that the substitution will lead to a change order if accepted, the substitution procedure has to be completed first. 

The best way to do it is to use a substitution request form. Though the AIA doesn’t publish one, the AIA trust does recognize the CSI form 13.1A (see below) and there are others available.

The Construction Specifications Institute (CSI) produces one of the most commonly used substitution request forms. Download a free CSI substitution request form for use on any construction project.

Supporting data

Now that you have your substitution request form, you’ll need some more supporting data to verify your request.

Substitution requests typically require supporting data to verify suitability, including:

  • Drawings
  • Product data
  • Materials safety data sheets
  • Samples
  • Tests
  • Reports 

All of these should be noted as included in the form. Also, remember to treat the substitution request as a transmittal to establish the date of submittal. This is important to prove that you gave the architect and owner ample time to make a decision.

Getting a substitution request approved

Remember the section of AIA201 that covers substitutions? It had only two requirements — “consent of the owner” and “evaluation by the architect.” To win approval, your request for substitution should be crafted with these two goals in mind. 

The criteria for each of these goals are typically very different. The architect’s decision is largely about the product, and the owner’s decision is about the money.

Convincing the architect

Technically, the architect has four options: Accepted, Accepted with Notes, Not Accepted, and Received Too Late. 

You want them to check the little box by “Accepted.” So how do you do that? Obviously, you want to submit your request on time and log it in your transmittals log to get rid of the “Received Too Late” option. Then, you have to sell it.

Again, the architect has a lot invested in the original choice and a great deal of liability on the line. If they accept your request, they’re as liable in court for this choice as they is for any other professional decision made in the design of the building. 

They’ve spent years evaluating the specified product and used it before with good results. Now you’re asking them to replace it with something they’ll probably only have a couple of hours to research and evaluate. If you want the substitution approved, it’s in your best interest to make this evaluation easy by providing answers to their concerns — which we can boil down to performance, durability, and aesthetics.

Here’s the things you’ll need to keep in mind for winning over the architect and getting your substitution request approved.


Let’s say you want to replace the specified aluminum storefront system with a competitor’s because it’s less expensive and more readily available. You need to establish that the performance is equal to the original spec’d item.

The architect will want to know if the dimensions are the same, if the drainage and weeping of the system are equivalent, if the aluminum extrusions are the same thickness, if the glass is the same and available with the same UV protection, etc.

To prove this, you should submit a performance spec from the proposed manufacturer. If you really want to make it easy to accept, highlight the similarities in the important sections.


The architect is legally liable for the performance of the design for the rest of its life, so they’re very concerned with performance of a material over time, not just at the point of substantial completion.

Will the gaskets on that proposed storefront deteriorate? How about the coating on the aluminum? Are doors with two hinges going to continue to seal as long as doors with three? Durability is hard to prove, so your best bet is to submit a warranty

It needs to provide at least the same coverage as the warranty for the specified product. Also, the manufacturer must be large enough and established enough for the architect to believe they’ll be around to honor that warranty. This goes a long way to convince the architect that the product is good — and that the choice you’re asking them to make isn’t going to land them in court.


You may think the two products look the same, but an architect sees things very differently. They’re very detail-oriented, so you need to get in front of this and give the architect what they need to evaluate the look of the material if it’s going to be visible.

For example, are the dimensions the same? The joints in the bricks are probably calculated to line up exactly with the edges of the storefront system, which in turn lines up with the joints in the metal panels. So the dimensions are important.

They’ll also want to know if the substituted material is offered in the same anodized and painted finishes and in the same colors, if it has the same coatings, if the gaskets (yes, the gaskets) are the same colors, and if the same hardware will fit. To prove this, you should submit a color sheet and material samples

Convincing the owner

Convincing the owner is typically a lot easier than convincing the architect. The owner is usually just focused on evaluating the proposed substitution by one criterium — cost. That’s it. They hired the architect to worry about the other stuff. 

The total cost of a substitution has three components: money, time, and beneficiary.


This is pretty straightforward. Your substitution request needs to tell the owner how much money the substitution will save. Is it cheaper? Less costly to transport or install? Whatever savings there are ought to be spelled out clearly.


Time is, of course, also money. If the substitution will shave a week off the schedule, that’s one more week that the owner can put the building into commerce and start profiting from it.


This is very important. The intended beneficiary of all of this saving of time and money is not the contractor, it’s the owner. There’s no reason that the owner should approve a change that benefits you instead of them.

So the submittal you present ought to reflect all the potential savings of money and time to be realized by the owner. Any savings you get are irrelevant for the purposes of the substitution request.

Substitution requests: Ensuring your risk and reward are balanced

In theory, the architect has evaluated the substituted product, the owner has approved it, and the contract documents have been changed to reflect that agreement. But in practice, there are other real risks involved in submitting for a substitution.

If something goes wrong with the product you submitted, someone will try and hold you liable. And any flaw in the information you provided can be used to lay the blame on that product’s failure at your feet. 

Any time the contract is changed it can cause disputes and delays in payment or claims of breach of contract. If there’s a problem with a specified item, your money can’t reasonably be withheld as a remedy. But if it’s with an item you substituted, an investigation could hold up your payment, as can delays with warranties. 

Technically, any savings of money or time realized by the substitution are to be passed on to the owner. The money being saved, of course, is theirs. And the time required to prepare the request and assemble the supporting documentation is hard, if not impossible, to bill for. 

The substitution still might be worthwhile for you if it saves you additional money because the substituted product is more familiar to you and, therefore, more efficient to install. Or, if you know both products and know the substituted product is superior and will prevent headaches for you down the road. Or, if you’re servicing a relationship with a supplier that makes a little extra effort worthwhile in the long run.

It’s always worthwhile to stop and consider if requesting a substitution is really in your best interest. In general, if the product you’re proposing as a substitute is something you know well, have used before and trust, it’s worthwhile to try and have it approved.

If you go about your substitution request the right way, you’ll likely get your approval and be on the way to getting paid for that portion of the work.