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An attic floor filled with gray blown cellulose between wooden joists, gable vent at the far end

Do it yourself, properly

DIY insulation

Most attic work is genuinely within reach of a careful homeowner over a weekend. Some of it is not, and we say which is which before you buy anything.

The order matters more than people expect. Air sealing before you add depth, baffles before you blow, and protective equipment before any of it — insulation work puts you in a confined space full of airborne fibre and decades of dust.

Four things that go wrong

None of these are obvious from the packaging, and each of them costs either money or performance.

  • A dust mask is not respiratory protection. Loose fibreglass and decades of attic dust need a half-mask with P100 cartridges. A paper mask is rated for nuisance dust and seals against nothing.
  • Baffles go in before the insulation, not after. Blow first and you bury the soffit vents, and a blocked vent causes exactly the moisture and ice damming you were insulating to avoid. Afterwards they are unreachable.
  • Compressed batts lose their rating. An R-19 batt squashed into a 3½ inch bay is not R-19 — it is closer to R-13. Buy the batt that fits the cavity.
  • You cannot judge depth by eye. Loose fill looks even and is not. Depth markers stapled to the joists before you start are the only practical way to confirm you hit the target.