How do you seal a flue hole?

Quote from the video:
Quote from Youtube video: Into your hole. And it will create its own seal no need for using sand and cement or silicone.

Can you put expanding foam around boiler flue?





It’s fine and perfectly safe. Even regular foam. Theirs at least 25mm gap between the exhaust flue and the outer air intake.

Can you seal a boiler flue with silicone?

If during installation Gas Safe registered engineers are unable confirm the suitability a sealant, e.g. an expanding foam product or silicone, from both the boiler and sealant manufacturers then the sealant product should not be used.

Can you use expanding foam around a gas flue?

It should be ensured in all installations that the wall is sealed to the flue inside the property by using expandable foam, by pointing with sand and cement or using any other suitable material.

What do you use to seal the flue pipe?

To air seal around combustion flues, use fire-rated caulk and UL-rated collars or sheet metal cut to fit and sealed with fire-rated caulk, while maintaining proper clearance between flue and combustible materials.

How do you seal around a pipe?





Quote from the video:
Quote from Youtube video: Hold the can of expanding foam upside down and direct the applicator inside the hole applying. Pressure as required shake. The can from time to time during use.

Can you insulate around boiler flue?

We fully understand the concern and we can assure you that it will be fine to insulate all the way up to the boiler casing. Please note that you want to keep the ASJ Max paper way from any open flame or touching a metal flue pipe, as any fiberglass insulation touching flue pipes can pose a fire hazard.

Is expanding foam heat proof?

Fire rated expanding foam can be used as an efficient seal against smoke and gas, providing up to 240 minutes fire rating. As well as being useful due to its excellent filling characteristics, fire rated foam has high thermal properties and provides acoustic insulation.

Can you use spray foam around chimney?

To keep a fireplace working properly, never use spray foam on the inside of the fireplace or the chimney, or on the damper. On the exterior surfaces of the fireplace and chimney, spray foam is fine because these surfaces won’t get hot enough to melt it or to cause any damage.

Does a boiler flue need to be sealed on the outside?



The wall around the flue needs to be sealed, both internally and externally. You can do this yourself. You do not need a registered engineer. Usually we seal externally with sand and cement mortar and plaster or filler on the inside.

Should a flue be sealed?

The flue must be sealed to the inner surface of the wall and the outer rubber flue sealing ring must be fitted. The rubber sealing ring provided for the outer surface is deemed an adequate weather seal to a flat, smooth surface.

Why is my boiler flue dripping?

The main cause of leaking boiler flues:



However, this means the waste products exiting the flue are much cooler than in non-condensing boilers. This cooler plume causes acidic condensation to form in the flue. This acidic water is the key problem when it comes to leaking boiler flues.