Can we use Selleys All Clear on outside of wood heater flue to seal old drill holes?

We installed an old free standing wood heater this week. On the roof outside where the flue is exposed (triple flue) we used Selleys All clear to fill some old drill holes that were dotted around the perimeter of the outer flue. It's where the old roof line used to meet the flue. Once we lit the fire (that night) the toxic fumes that came from the fire were unbearable. Is this product suitable for this application or should we have used something else to fill these holes which are no more than 0.4mm diam? I am concerned for our air quality (especially with young children) and don't want to light the fire again until we sort this out. I'm not sure how easy it will be to remove all of this sealant now it's there. Is it something that with the heat of the fire it will 'cure' and stop smelling after awhile? Our uncle who is a builder did the job for us, he told us it would smell for a bit but then settle down. But the smell was extreme and smelt very 'chemical based' and toxic.


All Clear is a solvent-based product. Depending on the thickness of the application, it can take several weeks for all of the solvent to evaporate. The final heat resistance of All Clear is also limited to around 70-80°C. For your application, Roof and Gutter Silicone would have been a more suitable alternative. Given the nature of the job, it would be best to remove the All Clear and replace it with the silicone. The silicone should be allowed to cure fully before the heater is used.

Topics: Sealants