1 Introduction
2 Materials and methods
System No. | Characterization | Binder | Wood preservera
| Target spreading rate [g/m2] | Film thickness [μm] | Maintenance product (1×brush) |
---|---|---|---|---|---|---|
1 | Primer | Acrylate resin | B,P | 1×160 brush | 69 | Opaque white medium build top coat |
Opaque white high build top coat | Alkyd-acrylate-PUR-resin | 2×125 brush | ||||
2 | Vacuum Impregnation (solvent borne) | Linseed oil alkyd resin | B, P | Vacuum impregnation | 130 | Opaque white medium build top coat |
Primer | Acylate resin | – | 1×120 flow | |||
Opaque white medium build top coat | Acylate resin | – | 2×120 flow | |||
3 | Impregnation | Alkyd resin | B | 1×140 brush | 39 | Semi transparent low build top coat |
Semi transparent low build top coat | Acrylate-copolymer-dispersion | – | 3×85 brush | |||
4 | Impregnation | Modified linseed oil | B, P | 1×200 dipping | 45 | Semi transparent low build top coat |
Primer | Alkyd-acrylate dispersion | B, P | 1×110 dipping | |||
Semi transparent medium build top coat | Acrylate- and oil modified PUR-dispersion | B | 2×100 dipping | |||
5 | Impregnation | Alkyd resin | B | 1×140 brush | 90 | Semi transparent medium build top coat |
Primer | Acrylate-copolymer | B | 1×70 brush | |||
Semi transparent medium build top coat | Acrylate-dispersion | 2×70 flow | ||||
6 | Impregnation | Alkyd resin | B | 1×140 brush | 38 | Semi transparent low build top coat |
Semi transparent low build top coat | Hybrid resin | 1×140 brush | ||||
2×105 brush | ||||||
7 | Vacuum Impregnation (solvent borne) | Linseed oil alkyd resin | B, P | Vacuum impregnation | 72 | Semi transparent medium build top coat |
Primer | Acylate resin | B, P | 1×85 flow | |||
Semi transparent medium build top coat | Acylate resin | 2×120 flow | ||||
8 | Impregnation | Acylate resin | B, P | 1×flow | 68 | Semi transparent medium build top coat |
Primer | Acylate resin | B, P | 1×85 flow | |||
Semi transparent medium build top coat | Acylate resin | 2×120 flow | ||||
9 | Impregnation | Modified linseed oil | B, P | 1×200 brush | 95 | Semi transparent low build top coat |
Primer | Alkyd- and acrylate dispersion | B, P | 1×110 brush | |||
Semi transparent medium build top coat | Acrylate dispersion | – | 2×100 brush | |||
10 | Impregnation | Modified linseed oil | B, P | 1×200 brush | 37 | Semi transparent low build top coat |
Primer | Alkyd-acrylate dispersion | B, P | 1×110 brush | |||
Semi transparent low build top coat | Acrylate-alkyd-resin | B | 2×110 brush | |||
11 | Primer | Hybrid resin | B | 1×140 dipping | 39 | Semi transparent medium build top-coat |
Semi transparent intermediate coat | Hybrid resin | B | 1×180 dipping | |||
Semi transparent medium build top-coat | Acrylate-PU-dispersion | 1×130 brush | ||||
12 | Primer | Hybrid resin | B | 1×140 dipping | 52 | Semi transparent high build top-coat |
Semi transparent intermediate coat | Hybrid resin | B | 1×180 dipping | |||
Semi transparent high build top-coat | Hybrid resin | 1×70 brush | ||||
13 | Semi transparent low build coat | Alkyd-acrylate-resin | B | 1×90 brush | 30 | Semi transparent low build coat |
Semi transparent low build coat | Alkyd-acrylate-resin | B | 1×90 brush | |||
14 | Semi transparent low build coat | Alkyd-acrylate-resin | B, P, W | 2×200 brush | 27 | Semi transparent low build coat |
15 | Semi transparent low build coat | Alkyd resin | B, P | 2×200 brush | 32 | Semi transparent low build coat, (solvent borne) |
U | Uncoated | – | – | – |
3 Results
3.1 Influence of imperfect coating application
3.2 Influence of coating systems and maintenance procedures
System No. | Horizontal areas at hand rails | Rounded areas at banisters | Vertical areas on front boards | Vertical areas on cladding | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Time in exposure | 18 Mo. | 24 Mo. | 24 Mo. | 18 Mo. | 24 Mo. | 24 Mo. | 18 Mo. | 24 Mo. | 24 Mo. | 18 Mo. | 24 Mo. | 24 Mo. |
Maintenance | No | No | Yes | No | No | Yes | No | No | Yes | No | No | Yes |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
4 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
5 | 1 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
6 | 1 | 2 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
7 | 2 | 2 | 1 | 2 | 2 | 1 | 1 | 1 | 1 | 2 | 2 | 1 |
8 | 2 | 2 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 2 | 2 | 1 |
9 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
10 | 2 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
11 | 3 | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 1 |
12 | 3 | 3 | 3 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 1 |
13 | 3 | 4 | 3 | 1 | 1 | 1 | 2 | 3 | 2 | 3 | 3 | 2 |
14 | 3 | 4 | 2 | 3 | 4 | 2 | 2 | 2 | 2 | 2 | 3 | 2 |
15 | 3 | 4 | 3 | 4 | 4 | 3 | 2 | 3 | 1 | 2 | 3 | 1 |
Uncoated | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 |
4 Discussion
4.1 Durability and maintenance procedures
4.2 Definition of limit states
Limit state | Film forming coatings | Non film forming coatings | State of coating | Defects |
---|---|---|---|---|
L-E | Esthetical Limit, Optical Deficiency | Esthetical Limit, Optical Deficiency | Only optical alterations | Change of gloss |
Change of colour | ||||
Growth of algae | ||||
L-D1 | Maintenance Interval | Maintenance Interval = Renovation Interval | Minor defects that do not require removal of original coating | Intensive chalking |
Cracks in coating film (without discoloration) | ||||
Cracks in coating by hail impact (without discoloration) | ||||
Flaking in single areas (<5 mm2, without discoloration around flaked area) | ||||
Superficial mould growth/blue stain | ||||
L-D2 | Renovation Integral | Coating degradation | Cracking | |
Blistering | ||||
Flaking | ||||
Hail damage | ||||
Discoloration around cracks | ||||
Penetrating mould growth/ | ||||
blue stain | ||||
L-D3 | Decay of Wood | Decay of Wood | Onset of decay in wood | Brown rot fungi |
White rot fungi | ||||
Wood boring insects |