Pourquoi faut-il laver les surfaces avant de peindre?

[fusion_builder_container type="flex" hundred_percent="no" equal_height_columns="no" menu_anchor="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" background_color="" background_image="" background_position="center center" background_repeat="no-repeat" fade="no" background_parallax="none" parallax_speed="0.3" video_mp4="" video_webm="" video_ogv="" video_url="" video_aspect_ratio="16:9" video_loop="yes" video_mute="yes" overlay_color="" video_preview_image="" border_color="" border_style="solid" padding_top="" padding_bottom="" padding_left="" padding_right=""][fusion_builder_row][fusion_builder_column type="1_1" layout="1_1" background_position="left top" background_color="" border_color="" border_style="solid" border_position="all" spacing="yes" background_image="" background_repeat="no-repeat" padding_top="" padding_right="" padding_bottom="" padding_left="" margin_top="0px" margin_bottom="0px" class="" id="" animation_type="" animation_speed="0.3" animation_direction="left" hide_on_mobile="small-visibility,medium-visibility,large-visibility" center_content="no" last="true" min_height="" hover_type="none" link="" border_sizes_top="" border_sizes_bottom="" border_sizes_left="" border_sizes_right="" first="true"][fusion_text admin_label="" awb-switch-editor-focus="" columns="" column_min_width="" column_spacing="" rule_style="" rule_size="" rule_color="" hue="" saturation="" lightness="" alpha="" user_select="" content_alignment_medium="" content_alignment_small="" content_alignment="" disable_idd="no" hide_on_mobile="small-visibility,medium-visibility,large-visibility" sticky_display="normal,sticky" class="" id="" html_attributes="W10=" width_medium="" width_small="" width="" min_width_medium="" min_width_small="" min_width="" max_width_medium="" max_width_small="" max_width="" margin_top_medium="" margin_right_medium="" margin_bottom_medium="" margin_left_medium="" margin_top_small="" margin_right_small="" margin_bottom_small="" margin_left_small="" margin_top="" margin_right="" margin_bottom="" margin_left="" fusion_font_family_text_font="" fusion_font_variant_text_font="" font_size="" line_height="" letter_spacing="" text_transform="" text_color="" render_logics="" logics="" animation_type="" animation_direction="left" animation_color="" animation_speed="0.3" animation_delay="0" animation_offset=""] Une surface propre permet à la peinture d'adhérer correctement et d'offrir une meilleure durabilité. [/fusion_text][/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]