Joints Joint Preparation & Joint Dimensions

Transcription

1 Joints Joint Preparation & Joint Dimensions

2 Joints: Definitions Sealant: Side of the joint: Depth of the joint: Width of the joint: Backing material: Movement of the joint: Material used to fill or seal the joint Area where the sealant connects to the joint The depth of a joint which is required to be filled with a sealant to get a correctly performing joint. The width between the to sides of the joint PU or PE material which is used in a joint to define the depth of the joint and to prevent 3 point adhesion Every change in the width of the joint due to Temperature difference Difference in humidity Movement of the building elements due to shrink/expansion Movement due to environmental circumstances (traffic, earthquakes,.)

3 1. Static joint Joints: Types of joint Movement of the joint between the elements is less than 7% (+/- = expansion/shrink) 2. Connection Joint Movement of the joint between the elements is between 7% and 15% (+/- = expansion/shrink) 3. Expansion joint Movement of the joint between the elements is between 15% and 25% (+/- = expansion/shrink)

4 SEALANTS: Possible causes of cracking within the sealant 3 point adhesion!!!! Excessive movements larger than max. allowed distortion

5 Joint design The sealant should stick only to the 2 sides of the joint a)no bond breaker tape: When the joint enlarges, the sealant will tear b) With a release bond breaker tape: The sealant strip may change freely of shape; less stresses and no risk of tearing.

6 Joint : preparation Where the depth of the joint is limited a flat PE tape is inserted to avoid 3 point adhesion.

7 Triangular joints To avoid 3-points adhesion Incorrect Correct Incorrect Correct

8 Joint : preparation In expansion joints PU or PE backer rods are used

9 SEALANTS : Joint dimensions Width Depth 1. Plastic & Plasto-elastic sealants Width must be equal to depth 2. Elastic sealants < 10mm wide - Depth equals Width =/> 10mm wide Depth equals half width Elastic sealants = Silicone, Polyurethane, Hybrid Polymer Plastic sealants = Butyl Mastics Plasto-elastic sealants = Acrylics

10 SEALANTS : Expansion Joints Movement Movement Movement < 10mm wide - Depth equals Width =/> 10mm wide Depth equals half Width < 10mm wide - Width equals Depth =/> 10mm wide Width equals half Depth Only elastic sealants may be used!

11 Sealant Stress

12 Preparation of the joint NEW JOINTS The joint surfaces need to be : Dustfree Stable (free of loose material) Free of grease Dry Use backing material to achieve the correct joint dimension and prevent 3 point adhesion Often preparation is needed: Surface preparation Primer Others

13 Preparation of the joint PREVIOUSLY SEALED JOINTS The joint surfaces need to be : Dustfree Stable (free of loose material) Free of grease Dry Use backing material to achieve the correct joint dimension and prevent 3 point adhesion Often preparation is needed: Cut out existing sealant Surface preparation (Grinding) Primer Others

14 Joint : preparation Moisture can prevent adhesion. Water pressure can loosen sealant. Primer can help.

15 Porous materials Primers To avoid capillary water pressure Primer 100 > PU-sealants Primer 150 > Silicones, Hybrid Polymers To avoid cracking due to porous substrates Typical problem for acrylic : too fast curing use diluted acrylic sealant as Primer onto the joint edges Non porous materials Surface Activator

16 Primer 100 & Primer 150 H 2 O H 2 O CO 2 H 2 O

17 Primer 100 & Primer 150 H 2 O H 2 O H 2 O Primer seals capillaries

18 Surface Preparation activating SURFACE ACTIVATOR: TRIPLE FUNCTION Cleans and degreases smooth surfaces Chemically improves adhesion on such surfaces Can improve surface tension on plastics Remark: Can leave a whitish haze on the surface

19 Performance of Soudal Surface Activator Surface Activator in shear test N/mm² SMX50 SF on lacquered alu 235 SMX50 SF on on blank raw alu 240 SMX25 FC on lacquered alu 240 SMX25 FC on on blank raw alu alu without SA with SA 20 25% increase in strength

20 AGED SEALANT EXPOSED Polyurethane fully exposed to the elements

21 WHAT ARE ISOCYANATES? POLYURETHANES contain isocyanates which is classified as a carcinogenic, some of the health effects of isocyanate exposure include: Cancer Eye irritation - watering and discomfort Irritation of the respiratory tract Dryness of the throat Tightness of the chest Difficulty in breathing Headaches Asthma attacks Reddening, swelling and blistering of exposed skin if not washed off Dermatitis Source: Guidance note Controlling isocyanate hazards at work (

22 SMX POLYMER ADVANTAGES ADHESION Porous and non-porous substrates Superior bonding to the widest range of substrates DURABILITY Extended life cycle Crack resistant High UV resistance Non-shrinking and non-bubbling APPLICATION Easy to work and tool Non-staining Faster curing ENVIRONMENTALLY SAFE Solvent free Low VOC Low odour Isocyanate free

23 MULTIBOND SMX25 FLEX & SEAL Soudal Sealants FEATURES & BENEFITS Low modulus Higher viscosity Highly flexible ±25% Internal & external UV resistant Paintable Shore A hardness of 25 7 colours

24 Soudal Sealants MULTIBOND SMX35 SEAL & STRETCH FEATURES & BENEFITS Elastic sealant Highly flexible ±20% Internal & external Multipurpose UV Resistant Paintable Shore A hardness of 35 7 colours

25 Soudal Sealants MULTIBOND SMX50 SEAL & STICK FEATURES & BENEFITS Fast curing Sealing & bonding Internal & external Trafficable UV Resistant Paintable Shore A hardness of 50 3 colours

26 SOUDASEAL FR FIRE RATED Soudal Sealants FEATURES & BENEFITS Elastic sealant Highly flexible ±25% Internal & external UV Resistant Meets Aust Standard AS Shore A hardness of 25 Paintable

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