Envelope Penetration Schedule Preparation Checklist

Start one list covering everything that will pass through the outside of the building, rather than separate lists for services, roofing and your own items.

The whole point is to see items belonging to different parties in one place, which is exactly where the gaps between them become visible.

Give each item its own line, with a short description, a rough position and a column for who forms it and who seals it.

The columns are what make it a schedule rather than a note, and the empty cells are the useful part of it.

Date each version of the list, and keep the earlier versions rather than overwriting them as items are added.

Seeing when each item joined the list is what shows whether things are being planned or discovered.

Start the list while it is obviously incomplete, and add to it as items emerge, rather than waiting until you think you know them all.

A list that exists and is wrong prompts corrections; a list that does not exist yet prompts nothing at all.

Mark items you are unsure about as uncertain rather than leaving them off, including things you are only considering.

A possible item raised early costs a conversation, and the same item raised late costs considerably more than that.

List any electric vehicle charge point, external socket, garden power or lighting supply you intend to have, including anything planned for later.

These are decided by the household rather than the design team, and they arrive with a trade who was not part of the coordination.

List any outside tap, irrigation supply, hot tub connection or garden water arrangement, including anything you are only considering.

Water leaving the building is straightforward to plan for in advance and disruptive to add once the outside is finished.

List alarm components, cameras, a doorbell, an aerial, a dish or any other communications item you expect to have on the outside.

Each of these is a small hole, and collectively they are the group most often installed after the building is complete.

List anything else the household will want that passes through — a pet flap, a letterbox, an extract for a utility, a vent for a flue you plan to add.

These are ordinary domestic items that nobody thinks of as penetrations until somebody is cutting a hole for one.

Write down anything you might want in future even if you are not doing it now, and mark those items as future rather than leaving them off.

A future item named now can sometimes be provided for cheaply in the sequence, which is never true once the building is closed.

Note for each of your own items who supplies it and who would install it, since those are frequently different from the main contractor.

Owner-supplied items installed by owner-appointed trades are precisely the ones that arrive outside anybody's coordination.

Ask for a list of every extract, ventilation terminal and air inlet that will pass through the outside, and add each to the schedule.

These are usually known in the design but are spread across drawings, and gathering them into one list is a straightforward request.

Add any flue or appliance terminal, and note that anything to do with a flue belongs with a suitably qualified and registered professional.

A flue is a penetration but it is also a regulated subject in its own right, and the list should reflect that distinction.

Flues and appliance terminals carry combustion products; their position and formation belong with a suitably qualified and registered professional.

Add every waste pipe, overflow, condensate discharge and anything else that leaves the building carrying water, however small the discharge is.

Small discharges are the items most often added on site by whichever trade needed one, which is how they end up unplanned.

Add the incoming supplies — water, electricity, gas, communications — and note where each enters and who is responsible for that crossing.

Incoming supplies are frequently arranged by parties outside the project, which is exactly why they belong on the same list.

Incoming supplies may only be arranged, altered or connected by the party responsible for each one, and their position is not settled within the project alone.

Ask whether anything structural passes through the outside, such as a support for a canopy, a balcony or a screen, and add each one.

These are the largest crossings and the ones least likely to be thought of as penetrations by anybody.

Anything structural passing through the outside of the building is a design determination for a qualified structural engineer and the envelope designer together.

Note separately any rooflight, opening or aperture formed in the structure, and ask whether those are being handled as a different subject.

An opening formed to receive a unit is a different arrangement from a hole cut for something that keeps working, and mixing them confuses the list.

For each item, note whether it crosses a wall, a roof or something below ground, since those are meaningfully different situations.

A crossing on a horizontal surface is a joint in the plane most likely to hold water, which makes it a different question from a wall.

Mark each item on a photograph or drawing of the relevant elevation or roof plan, rather than describing its position in words.

Positions described in words move; positions marked on an elevation do not, and the marked drawing is what gets discussed.

For anything on a roof or a terrace, ask where it sits relative to where water travels and to any outlet, and note the answer.

Where a crossing sits on a falling surface changes how much water reaches it, which is a design consideration rather than a placement convenience.

Ask which continuous layers each item crosses, and ask for them to be named individually rather than described collectively.

A single item usually interrupts several things that were each continuous for a different reason, and each has its own remedy.

Ask whether any item passes through construction with a fire-resisting function, and record that this is a separate determination by qualified professionals.

Naming it on the list is useful; deciding anything about it is not, and the distinction should be explicit in the schedule.

Penetrations through fire-resisting construction are governed by tested systems and by qualified professionals, and nothing here addresses them.

Note which items move, vibrate or change temperature in use, and ask whether that has been considered at each crossing.

An item that moves is a different problem from one that does not, and it is the property most likely to be overlooked.

For each item, ask who forms the opening itself, and write a name rather than a trade in that column.

The opening frequently belongs to a different package from the thing that passes through it, which is the split that causes trouble.

Ask who is responsible for sealing each crossing and returning the layers around it, and record that separately from who forms the opening.

This is the item most often in nobody's scope, and a separate column makes its absence visible immediately.

Go through the list and raise every line where either column is empty, treating an empty cell as the question rather than an oversight.

The list's purpose is to produce those questions, and working through them one line at a time is what makes it effective.

Pay particular attention to your own items, and ask explicitly who would form and seal each of those rather than assuming the contractor will.

Owner-supplied items sit outside the contractor's scope by definition, which is exactly why they need naming.

Send the completed list to the people responsible and ask them to confirm the entries against their own names.

Confirmation against a written list is quick to obtain while the project is live and impossible to obtain afterwards.

Ask when the outside of the building is closed at each stage — sheathing, insulation, covering, cladding — and note those dates.

Each stage closes a different set of options, and the dates are known to the contractor long before they arrive.

Send the current list to everybody involved shortly before each of those dates, rather than only once at the start.

A list circulated at the right moment prompts people to remember items; the same list sent at the start is read once and filed.

Ask whether provision can be made now for anything on the list marked as future, and record what is provided and where.

Provision made while both sides are open is a very different proposition from an alteration afterwards.

Ask for one explicit conversation before the building is closed, going through the list line by line with the people responsible.

A single deliberate review at the right moment catches more than any amount of correspondence beforehand.

Where an item is added after that point, record what it was, who decided it and how it was dealt with.

Late items happen, and recording them honestly is what stops them disappearing from the building's history.

Ask for each crossing to be photographed before it is covered by insulation, cladding or a finish, and collect those photographs.

The photographs are the only account of what is inside each hole once the outside of the building is finished.

Mark the final positions of every crossing on a drawing or a photograph of each elevation and the roof, and keep that with the building papers.

A marked-up record is the single most useful document to give to anybody working on the outside of the building later.

Against each position, note what the crossing is for, so that a future reader can tell an extract from a condensate discharge.

An unlabelled hole in a record is only marginally more useful than no record, and labelling costs nothing at the time.

Put the final list into the handover file with the rest of the building documents rather than keeping it in the project correspondence.

Project correspondence is cleared out after completion, and this is one of the documents most worth keeping past that point.

Keep the list where you will find it before any future work on the outside of the building, and show it to whoever is carrying that out.

Later work is where these crossings are most at risk, and the list is what makes them visible to somebody who was not there.