Building the walls up to roof level

Block, timber frame and insulated concrete formwork walls on an Irish self-build: what to check before work is covered, and who signs off.

Last reviewed 20 October 2026 6 min read6 sources

Key points

Walls are where the method you chose shows on site: block goes up course by course over weeks, a timber frame can be erected in days, and insulated concrete formwork (ICF) is poured in lifts.
Cavity trays, wall ties, lintels and insulation continuity are all hidden once the wall is closed, so inspect them while they are open.
A timber frame must be kept dry. Wet frame timber is a bigger risk than a slow build.
Photograph openings, lintel bearings and cavity details at each floor level, with a tape in view.
Many lenders pay a stage when the walls reach wall plate or first-floor level, so check what your lender's inspector needs.

This is the stage when the house starts to look like a house. The walls rise from the slab to the point where the roof can start, including any upper floor. What you see on site depends on the method you chose: block, timber frame or insulated concrete formwork (ICF). The checks they share come first, then the differences. To choose between them, read timber frame, block or ICF.

What happens in order

Setting out the first course. The walls are set out from the foundations, level and square, with door and window openings marked. A mistake in the first course carries all the way up.
Lower walls to DPC. Walls come up to damp-proof course level. See substructure and floor slab.
Walls to first-floor level. Openings are formed with lintels over doors and windows. External walls are built with the insulation detail the design calls for.
First floor. Joists or precast floor units go in, with their bearings on the walls and any restraint straps in place.
Walls to wall plate. The upper storey, if any, goes up to wall plate. Gables are completed later, with the roof.
Wall plate fixed. The timber plate that will carry the rafters or trusses is fixed down with the specified straps and anchors.

Block (cavity wall)

Most Irish houses are built from concrete block, usually a cavity wall with an inner leaf that carries the load, a cavity with insulation, and an outer leaf that is rendered or clad.

Wall ties link the two leaves. They must be the specified type and spacing, clean, and sloping slightly outward or level, so water does not run across them.
Cavity trays and weep holes at the base of the cavity, over lintels and at roof abutments guide water out. A missing tray often shows up as damp inside a few years later.
Insulation has to be continuous, fit tight to the inner leaf and be protected from mortar droppings. Bridges at lintels, corners and the first-floor junction lose heat.
Lintels are checked for bearing: how far they rest on the wall at each end, as shown in the drawings.
Mortar is mixed in the proportions in the specification. Walling in frost or rain without protection weakens it.

Timber frame

A timber frame house is made as panels in a factory, delivered to the site and erected on the slab. It can go up in days, but the work around it needs planning.

Lead time. Frames are ordered months ahead. Order dates and your builder’s programme must match, or the site waits.
Keep the frame dry. Timber that is rained on for weeks can swell and trap moisture behind membranes. Ask how panels are covered when the roof is not yet on, and have a moisture check recorded before the plasterboard goes on.
Fire stops and cavity barriers limit the spread of smoke and flame in cavities, and they are easy to leave out. Photograph them.
The membrane (airtightness and vapour control layers) must be continuous and taped. See insulation and airtightness.
The outer leaf (brick, block, render board or cladding) goes up after, often by a different trade.

The timber frame supplier’s own inspection or a certificate for the frame can support the certifier’s records, but it does not replace the certifier’s inspection of the site work.

ICF (insulated concrete formwork)

ICF uses hollow insulated blocks stacked like toy bricks, reinforced and filled with concrete. It is a more specialist method.

The first course must be level and well set out, because the pour cannot fix a wavy line.
Reinforcement must be in the correct place before each lift of concrete.
Concrete is poured in lifts, with vibration, and the blocks can bow if poured too fast. A trained crew matters more than the system.
Inspect before the pour, not after: the concrete hides the reinforcement and any gaps.

Who signs off

Do not rely on memory. A wall of blockwork looks the same whether the cavity tray is in or not, and a certifier who visits on a day when the lintels are already built over can only record what is still visible.

Your assigned certifier will list wall stages in the inspection plan. Structural openings, lintel bearings, cavity details and first-floor connections are typical inspection points. If you use a timber frame, ask whether the plan includes the factory production or whether it relies on the supplier’s documents. See the assigned certifier and building regulations.

Your engineer should confirm any change you ask for on site. Moving a window or widening an opening affects lintels, loads and heat loss.

What to check and photograph

With a tape in each picture, record:

Each opening and its lintel, showing bearing on each side.
Cavity trays and weep holes at the base of the cavity and over openings.
Wall ties and insulation fixings in a section of cavity before it is closed.
Floor bearings and restraint straps.
Fire stops and cavity barriers.
The tops of walls, with the wall plate fixings.
Any change from the drawings, and the written instruction behind it.

Check dimensions as you go: levels, door and window sizes against the order, and the thickness of the cavity.

What goes wrong, and what it costs

Most wall defects are cheap to correct while the wall is one course high and expensive once the roof is on. Walk the site yourself once a week and compare what you see with the drawings, even if you are not an expert. Questions are free.

Cavity bridged by mortar or by insulation pushed out of place. Damp and cold patches show up inside.
Out-of-square walls. The windows and roof no longer fit, and the fix is expensive.
Missing lintels or poor bearing. A structural issue that must be solved by an engineer.
Windows ordered to the wrong size. Measure on site before the order is final if openings changed.
Rain damage to timber or insulation. The remedy is drying and replacing damaged material, with a delay.
Winter working. Cold or wet weather needs protection, and the schedule must allow for it.

Payments, site risks and cover

Wall stages are also where variations pile up: a bigger window, a moved door, an extra steel beam. Ask for a price in writing before the change is built, and give the certifier the revised drawing so that the completion certificate matches what exists.

This is often a lender’s stage, called “wall plate”, “first floor” or “walls up”. Confirm which one applies and whether the lender’s inspector wants to see it before the roof starts. Your builder’s payment schedule may tie payments to different points than the lender’s, so keep the stage payment planner up to date.

Open walls without a roof are exposed. A storm can damage unprotected frames, scaffolding and stored materials. Scaffolding creates a falling and theft risk, and a stranger on site can be injured. Make sure your contract works and public liability cover is current, and check whether the cover includes damage by weather before the roof is on. See insurance when you project manage and the cover checker.

Before the roof starts

The walls are level at wall plate and the plate is fixed down.
Inspections are recorded and photographs filed.
Materials for the roof are ordered. Trusses and tiles have lead times.
The next stage: roof and weathertight shell.

Common questions

What is wall plate level?

The wall plate is the timber that sits along the top of the external walls and carries the roof. Wall plate level means the walls are built to the point where the roof structure can start.

How long do the walls take?

For a typical house, block walls often take four to eight weeks depending on size, weather and the number of bricklayers. A timber frame is manufactured off site and can be erected in days once it is delivered. Allow for the lead time on the frame, which can be several months from order.

Do I need to inspect lintels and cavity trays myself?

Not alone. Ask your designer or certifier to inspect and record them, and take your own photographs as well. They cover the openings and the transition between floors, which are common leak points.

Can the walls get wet while the house is open?

Block and concrete can tolerate rain better than timber and insulation, but standing water, saturated insulation and wet mortar in cold weather cause problems. Protect the tops of walls and keep timber frame components covered until the roof is on.

Sources

Last reviewed 20 October 2026. Rules and figures change, so confirm anything important with the source before you rely on it.

Building Control (Amendment) Regulations 2014 (S.I. No. 9 of 2014)Irish Statute Book
Code of practice for inspecting and certifying buildings and worksNational Building Control and Market Surveillance Office
Nearly zero energy building standardSEAI
Guidance for homeowners on construction project supervisorsHealth and Safety Authority
Building Control Regulations 1997 (S.I. No. 496 of 1997)Irish Statute Book
Self-build and stage payment checklistLender checklist

This guide is general information about self-building in Ireland, not financial, legal or insurance advice. Get advice that fits your own situation before you make decisions.