Material Substitution Request Review Checklist

Write down the product originally specified and the one proposed, with the full reference for each, rather than a family name or a description.

A reference transcribed loosely can point at a different item entirely, which is the origin of a surprising number of substitution problems.

Note who is proposing the substitution and in what capacity, since a proposal from a supplier and one from a designer carry different information.

The origin tells you what the proposal was optimising for, which is not usually stated.

Ask whether the substitution affects only the item itself or also anything installed with it, such as fixings, adhesives or accessories.

Products frequently come with matched components, and substituting the main item can quietly substitute several others.

Ask where the substitution applies, and whether it affects every location the original was to be used or only some of them.

A partial substitution leaves two products doing the same job in different places, which is worth knowing about deliberately.

Ask for the product documentation for the proposed item, and read it yourself even if you do not understand all of it.

The published material is direct that product literature is sometimes the governing document for how an item is to be installed.

Ask for the proposal in writing with both references shown, rather than agreeing to something described to you in a conversation on site.

A verbal substitution leaves no record of what was actually offered, which is the thing most often disputed afterwards.

Ask plainly why the substitution is proposed, and record the answer in the words used rather than in your summary of it.

Availability, preference and a practical difficulty on site are different reasons that lead to different questions.

Ask whether the original is genuinely unobtainable or merely inconvenient to obtain, and what was checked before the question came to you.

These sound identical in a message and are entirely different situations.

Ask whether something found on site prompted the proposal, since a substitution can be the visible end of a discovered condition.

A substitution proposed because something did not work is a much more significant event than one proposed for supply reasons.

If the substitution follows something found on site, ask what was found and whether the designer has seen it before accepting the product.

Ask who has already looked at the proposal, and whether anybody who specified the original has been asked about it.

Substitutions frequently reach the owner before reaching the person who chose the original.

Ask how long the decision can wait and what happens if it does, so the urgency is a fact rather than an impression.

Urgency asserted in a message often turns out to be softer than it sounds when described in terms of work.

Ask what the item has to bond to, sit on, drain into or join, and whether the proposed product is intended to work with those things.

Many products are designed as part of a set, and their behaviour depends on what they are used with.

Ask whether the original was part of a set from one source, and whether substituting one item takes it outside that set.

Leaving a manufacturer's own set is a significant change even when each individual product seems equivalent.

Whether a product from a different source can be used within a system is a matter for a suitably qualified professional and for the manufacturers concerned.

Ask whether accepting the substitute means anything adjacent also has to change, and whether those changes have been identified.

A substitution that propagates is a different proposition from one that stops at the item itself.

Ask what happens where the substitute meets whatever continues past it, and whether that junction was detailed for the original product.

A detail drawn for one product does not automatically describe how a different one meets the same surrounding construction.

Resist judging the substitution on how it looks or on how similar it seems, and keep the question on what it has to work with.

Visual similarity is the least informative property of a product in this context and the most available to an owner.

Ask what the proposed product requires of whatever it is applied to or fixed into, and whether that condition exists on this project.

Substrate conditions are the commonest requirement in product literature and the one most often discovered too late.

Ask whether the product requires anything of the person installing it, such as particular training or an approval from the manufacturer.

Some products are only supplied with their arrangement intact if installed by somebody the manufacturer recognises.

Whether an installer meets a manufacturer's requirement is confirmed with the manufacturer, not taken from a statement on site.

Ask whether the product requires anything to happen before or after it, such as a waiting period or a following layer within a certain window.

Sequence conditions attached to a product are a programme matter as much as a technical one.

Ask whether the product has requirements about the conditions it is installed in, and who is responsible for confirming those are met.

Conditions during installation are a stated requirement for many products and are rarely anybody's explicit responsibility.

Ask whether anything has to be recorded or seen before a following layer goes on, and add that to your concealed-work list if so.

Product documentation sometimes requires a stage to be recorded, which is easy to miss when nobody has read it.

Ask who has actually read the documentation for the proposed product against the conditions on this project, rather than reading it in general terms.

Literature is frequently supplied and not read, which is the practical route by which its conditions go unmet.

Establish what the original product came with, whether a guarantee, documentation or some supplier arrangement, before trying to compare the substitute against it.

You cannot tell what is being given up without knowing what was there, and that is often unrecorded.

Ask what comes with the proposed product, in what form, and what the owner has to do to keep it in place.

Arrangements offered with a product usually carry conditions about installation, use or maintenance.

Ask what the substitute requires of you after completion, such as maintenance or restrictions on use, and whether those differ from the original.

Conditions inherited by the owner are the part of a substitution that outlives everybody involved in making it.

Any maintenance or use condition attached to a product is set by the manufacturer; confirm it with them rather than relying on what you were told on site.

Ask whether the substitution affects any wider warranty on the project, and put that question to the warranty provider directly.

A project-level arrangement can reference specified products, and only the provider can say whether a change matters.

Ask what documentation will be provided at handover for the substitute, and add it to the list you expect to receive.

Documentation for a substituted product is the item most often missing from a handover pack.

Ask whether the person who specified the original has been asked, and send the proposal to them if they have not.

The specifier is the only party who knows what the original was chosen for, which is the whole question.

Ask whether any other designer needs to see it, particularly where the item interacts with structure, water or services.

A product can be acceptable in one discipline's terms and significant in another's.

Ask whether any third party has an interest, such as a warranty provider or an authority, and put the question to them directly.

Third-party requirements about products are set by those parties and cannot be inferred from the project team's view.

Whether a substitution affects anything agreed with an authority or a warranty provider is confirmed with that body rather than assumed.

Avoid letting a substitution proceed simply because nobody objected, and give an explicit answer even where that answer is to refer it onwards.

Acceptance by silence is how a substitution ends up with nobody having considered it at all.

Record who accepted the substitution, on what date and on what basis, rather than recording only that it was accepted at some point.

The basis is what makes the decision explicable later, particularly if the product behaves unexpectedly.

Record both products against one another, with the date and the reason, rather than simply replacing the original in your records.

The original reference is what allows anybody later to see that a change happened at all.

Ask whether the specification or schedule will be marked up to show the substitution, and who is responsible for doing that.

A specification that still names the original is a document that has stopped describing the building.

Ask which drawings or details referenced the original product, and whether any of them need to change as a result.

Details drawn around a particular product are frequently left unchanged when the product is replaced.

Log the substitution as its own entry rather than as an amendment to the original choice, since it has a different origin.

A substitution has a different initiator from your original selection and may carry consequences the original did not.

Where the substitution applies in some places and not others, record exactly which of the two products ended up in each location.

Two similar products in different rooms is an ordinary outcome and an impossible one to reconstruct later.

Carry the substitution record into handover so that what was installed, rather than what was specified, is what the papers describe.

Handover documents that describe the specified product are the reason later repairs start from the wrong item.