Author Archive

Caulking Wood Siding and Trims

Caulking is a material used for sealing joints in various substrates. The benefits of caulking are to provide an aesthetically pleasing finish to the substrate and to prevent moisture from penetrating, causing deterioration. However Caulking is not suitable for use on all substrates and when used on wood siding, can actually cause more harm than good, as shown below

Failed Caulking On Wood Siding

Caulking is not recommended for use on butt-joints on wood siding, as siding boards are designed to expand and contract with the elements in ways that the caulking cannot. For example, when heated in the sunlight the wood siding will expand both sideways and outwards.

This was a problem found during an inspection of painting preparation work on a recent repaint project. There was evidence of the caulking failing between all of the butt joints (see image above). The use of caulking was an attempt to correct other issues with the building, however, the caulking failed causing moisture to become trapped behind it resulting in wood rot and failure of both the coating and the caulking.

Another area that Caulking should not be used is on trim boards that sit on top of the siding. On most homes the trim goes up after the siding is installed, which creates a large gap that should not be caulked. It requires strip flashing instead of caulking to deflect moisture from behind.

The air needs to circulate behind these boards and the opening allows for any trapped moisture to be released. The bottoms of sidings boards should not be caulked for the same reasons.

Caulking should be used sparingly on any external wood siding projects, and as seen in the inspection described above, and not on wood butt-joints because of the expansion and contraction in the elements.

The caulking was used in an attempt to correct other issues, but it failed and offered no protection resulting in the costly requirement of having to replace all of the deteriorated wood siding and trim.

Board of Directors

Board List

Terry Jennett

Calibre Coatings Ltd.
6224 29 Street SE
Calgary, Alberta T2C 1W3
Phone: (403) 287-7792

Past President
Sandy Baker


Vice President, North
Mark Chambers

O’Canada Contractors Ltd.
3636 109th Ave
Edmonton, Alberta T5W 0G7
Phone: (780) 940-1769

Vice President, South
Chris Kulbaba

Calibre Coatings Ltd.
6224 29 Street SE
Calgary, Alberta T2C 1W3

Dave Schiffers

RCI Coatings Ltd.
36, 11010 – 46 Street SE
Calgary, Alberta T2C 1G4
Phone: (403) 992-5841

Rathe Mokelky

SuperPro Painting Systems of Calgary Ltd.
Bay 10, 1235 – 64 Street SE
Calgary, Alberta T2H 2J7
Phone: (403) 966-7201

Bob Derochie

Derochie Painting Ltd.
4010 – 24 Avenue N
Lethbridge, Alberta T1H 6L7
Phone: (403) 380-4248

Ryan DeSouza

Final Touch Decorating
44 Abbercove Way SE
Calgary, Alberta T2A 6Z3
Phone: (403) 475-6214×2

Nathaniel Sarabura

United Paint & Coatings Experts
7-624B Beaver Dam Rd NE
Calgary, Alberta  T2K 4W6
Phone: (587) 779-5794

Technical Chair
Tom Pharis

Cloverdale Paint Inc.
640 – 42 Avenue SW
Calgary, Alberta T2G 1Y6
Phone: (403) 287-0014

Tips of Cleaning Interior Walls

Interior walls can be subject to all kinds of marks such as dirt, scuffs or hand prints. Cleaning interior walls requires some consideration, excessive cleaning or cleaning using inappropriate cleaning methods can cause irreparable damage to the coated surface.

Within this article we discuss the best practices for successfully cleaning interior walls.

Determine substrate
Before you carry out any cleaning it is best to determine what type of coating has been previously applied to the surface or substrate (if any)

Low gloss coatings –  are less durable than higher gloss coatings making them more susceptible to damage from harsh abrasion and chemical cleaning.

High gloss coatings – are more durable, so will endure more abrasion and chemical cleaning, but are less often used on interior walls because they tend to enhance any surface defects, making them more visible.

Cleaning solutions When choosing a cleaning solution check for any abrasives, alcohols or harsh chemicals. Low gloss latex coated interior walls especially cannot endure this type of cleaning product, but some other products would fail if alcohol, bleach or other harsh chemicals are applied to them.

Test patch
Before commencing any cleaning on the full surface, carry out a test patch in an out-of-the-way area to assess the effect on the coating.

Rinse thoroughly
Whatever cleaning solution is used must be removed thoroughly or risk leaving streaking, especially if repainting the surface over the solution.  Washing procedures should always be from the “bottom up” to also avoid streaking.

For best results, if you know what coating has been used to coat the surface, speak to the coating manufacturer about any recommended cleaning products or methods to be used.

Products tested by MPI are listed in the MPI Approved Products List (APL) under the relevant standard #. Look out for the MPI Approved Product Label on paint cans!
CLICK HERE for more information.