Lintels and Reveals in Ireland — The Detailing That Makes or Breaks Airtightness
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Lintels: structural beam over an opening. Reveals: the wall detail around windows. Critical for airtightness and thermal bridging.
Lintels: structural beam over a window or door opening, specified by the engineer. Concrete, steel, or insulated steel (for thermal performance). On a 150 m² house, expect 8–15 lintels. Reveals: the wall detail around the window frame — the bit where the wall meets the window. Critical for airtightness and thermal bridging. The most under-detailed part of most self-builds. A continuous airtightness layer, sealed at the window frame, is the key. Most airtightness failures are at window reveals, not at the window itself. The detail: a continuous membrane from the wall airtightness layer, turned into the window frame, sealed with a gasket or sealant. The architect details this; the builder builds it; the airtightness test verifies it.
When this matters most
You're at design stage and need to detail the openings.
When this doesn't apply
The walls are built and the windows are in.
Sources
Building Regulations 2023, TGD-L. https://www.gov.ie/
Frequently asked questions
What is a lintel in a self-build?
A structural beam over a window or door opening. Specified by the engineer. Concrete, steel, or insulated steel. Most 150 m² houses have 8–15 lintels.
What is a window reveal?
The wall detail around the window frame — the bit where the wall meets the window. Critical for airtightness and thermal bridging. The most under-detailed part of most self-builds.
How do I detail a window reveal for airtightness?
A continuous membrane from the wall airtightness layer, turned into the window frame, sealed with a gasket or sealant. The architect details this; the builder builds it; the airtightness test verifies it.
When this matters most
You're at design stage and need to detail the openings.
When this doesn't apply
The walls are built and the windows are in.
Where to go next
Next decision
The next step in your build sequence.
Branch into
Adjacent decisions at the same stage.
Watch out for
Common mistakes, hidden costs, gotchas.
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