Sealing the chimney

Technologien und Beratung für den Betonbau - B.T. innovation

Reliably seal chimney

A vulnerable spot on the roof is the chimney penetration, regardless of whether it is a gable or flat roof. If holes and broken plaster are visible on the chimney at this point, water can penetrate the masonry and cause major damage. With a bit of manual skill, you can seal the chimney against the roof yourself. The choice of the product required for the repair depends on the type of chimney, the size and position of the leak. For this purpose, BT innovation provides different variants that simplify sealing.

BT waterproofing products are excellent for this purpose:

  • To seal the chimney comprehensively and permanently
  • Repairing dents and cracks in the chimney
  • Reliably renew the sealing of the chimney

This makes the secure sealing of your chimney quick and easy to realise.

Schornstein abdichten, Anwendungsbereiche

BT solutions for sealing masonry chimneys

InnoElast® – Effective sealing of joints and cracks on chimneys

Over the years, the sealing of the chimney suffers from material fatigue and exposure to the elements. As a rule, not only rain, storms, cold and heat play a role, but also the power of UV radiation. On this basis, when choosing your waterproofing material, make sure that it is waterproof, airtight, elastic and UV-resistant.

Usually it is not the entire seal around the chimney that is leaking. Rather, cracks can form over the years or parts of the joints can peel off. Under these circumstances, time and money can be saved and the focus can be on the precise repair of individual spots. Leaky joints on the chimney or at the transition to the roof can be permanently sealed with InnoElast Type 1 and Type 2.

Advantages of InnoElast® Type 1

  • Solvent-free
  • low-shrinkage
  • Applicable on damp substrates from -3°C
  • Weather and UV resistant
  • Permanently elastic
  • Up to 25% motion absorption
  • Applicable without primer

Advantages of InnoElast® Type 2

  • Solvent-free and low shrinkage
  • Applicable on damp substrates from -3°C
  • Weather and UV resistant, high resistance to chemicals
  • Permanently elastic
  • Up to 10% motion absorption
  • Applicable without primer
  • Pressure waterproof up to 0,48 bar
Fugenabdichtung Haus und Garten


Using a tubular bag gun, InnoElast® Type 2 is applied to a clean substrate and then cures effectively. The skin formation time is between 2 and 3 hours (type 1) and 15 minutes (type 2) at a room temperature of 23°C and humidity of 50%, the curing time is 3mm in 24 hours. A primer is not required beforehand. However, it is recommended to insert a joint filler cord and tape the edges. Pressing and smoothing creates a strong bond with the joint edges.

When do I decide on InnoElast® Type 1 and when on Type 2?

InnoElast® Type 1:

  • for movement joints with movements up to 25%
  • for joints that are only sprinkled and where no water pressure is applied

InnoElast® Type 2:

  • for joints exposed to chemicals (acids, alkalis, selected fuels)
  • for joints exposed to pressure water up to 4,8m water column
  • for joints that are adjacent to bituminous materials / coatings and should be tight.

Instructions - Processing as a joint sealant

ProElast® – Sealing of damaged areas and renewal of the entire chimney sealing system

The ProElast® system of foil and foil adhesive is suitable for sealing damaged surfaces on the chimney. Bestehend aus widerstandsfähiger EPDM-Dachfolie und dem extrem haftenden Flächenkleber InnoElast® sorgt sie für eine dauerhafte und extrem starke Verbindung. The ProElast® system is characterized by unlimited waterproofing, high weather resistance and simple processing.

With older chimneys or roof renovations, it may be necessary to renew the entire sealing surface to the chimney. Permanent stress can cause damage to the roofing felt or the sealant. Therefore, it is not worthwhile to start at every single spot if it is foreseeable that a large number of cracks will form. A complete renovation of the chimney seal prevents further leaks from occurring. Sealing the chimney with our products should only be done from the outside and not from the inside.

ProElast® System – Advantages

  • Pressure waterproof up to 2 bar
  • Application on damp, ice-free substrate from 3°C
  • Weather and UV resistant
  • With InnoElast® type 2 = high chemical resistance
  • Applicable without primer
ProElast Referenzen 3


After applying InnoElast® adhesive to a clean substrate, it is spread by means of a notched trowel. The sealing film is then glued centrally over the joint so that no air bubbles remain. The edges are then sealed with InnoElast® Type 1 or Type 2. Short curing times enable fast further work. The skin formation time is 2-3 hours for InnoElast® Type 1 and 15 minutes for InnoElast® Type 2 at a room temperature of 23°C and a humidity of 50%. Within 24 hours, a layer thickness of 2 to 3 mm, at a room temperature of 23°C and humidity of 50%, cures effectively. In this way, you reliably seal construction joints, predetermined crack cross-sections and movement joints.

Instructions - Processing as surface sealing

LiquidElast® – Your professional for waterproofing on uneven substrates

Repairs to corners that are difficult to access, angled transitions or surfaces with very uneven substrates can also be carried out with the paintable LiquidElast Type S. To make the repair durable, sand or slate chippings should be finally sprinkled into the top layer of the liquid film.

FlaechenElast Anwendung Teaserbild

LiquidElast® – Advantages

  • Pressure waterproof up to 1,0 bar
  • Wear resistant and resistant to many chemicals
  • Applicable on damp substrates from 0°C
  • Crack-bridging up to 5 mm
  • Permanently elastic

Instructions - Processing as surface sealing

Sustainable protection against moisture

When working on chimney sealing, it is not only the material used that is important. You should also ensure that your roof is properly drained. To ensure that the repair is as sustainable as possible, the pitch of the roof must be taken into account. While applying a new layer for waterproofing, make sure that the material is applied evenly. In addition, larger masses of water must be reliably drained from the roof with rain gutters and downpipes. This makes it necessary to check the chimney seal regularly – at least once a year.

It is advisable for do-it-yourselfers and professionals to observe the weather conditions. To carry out work on the roof, calm and dry weather is advantageous, especially for the durability of the waterproofing. With BT innovation products, however, repairs can be carried out in bad weather. Necessary safety measures are to be taken. Safeguarding is ensured with the installation of a roof step or a small platform. In addition, necessary utensils should be positioned within easy reach. When applying the waterproofing material, ensure that the surfaces are clean and dry and allow the compacted areas to cure for a few days.

When working on your chimney liner, unlike many trades, you can follow the motto “a lot helps a lot”.

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