[yournamehere]

Hi All,
I'm new here and have found a wealth of info in the past, so thank you.

I'm currently working on a project where I'm looking for advice on working with pre-primed Western Red cedar (WRC) beveled siding for the first time. Typically I'd work with bare (dry) WRC , apply a coat of tannin-blocking primer and apply two top coats of solid stain. I've been told by the lumbar supplier that the siding was delivered with an oil base with an acrylic top coat. Given that well below 50 here in the Northeast, I cannot apply the final coat of solid stain if the siding is install now. So, I planned on applying the final finish in a heated space with applying stain to all sides. Is this overkill, or should I have the installer put up the siding and wait until the Spring? I've always been advised to apply two finish coats on all sides of the cedar before installation. Is an oil base with acrylic top coat going to keep backside of the cedar properly protected?

 

[PressurePros]

The backside is plenty protected with an oil base and acrylic topcoat. That will last forever with no exposure to elements. Go ahead with the installation. Use a pure acrylic/water borne for the final topcoat.

 

[yournamehere]

Thanks for the advice. Any recommendations for prepping for the final top coat in the Spring?

 

[PressurePros]

Thanks for the advice. Any recommendations for prepping for the final top coat in the Spring?

Bleach wash to make sure you have no mold and remove any surface dirt. Look for something called a downstreamer to get the bleach onto the house. You can add a little dish soap for suds and cling.

 

[Damon T]

This way your nail heads will get coated too.
And you can caulk as needed and cover with stain in the spring.

 

[ridesarize]

If the siding has primer and factory topcoat of different color or feels dry or chalky, then double coat outside of boards after installation. Just my opinion. You would use large stain brush to backbrush, no?

 

[yournamehere]

The backside is plenty protected with an oil base and acrylic topcoat. That will last forever with no exposure to elements. Go ahead with the installation. Use a pure acrylic/water borne for the final topcoat.

What if the backside only has primer? Just found out from the supplier that this is the case. Only the frontside has a top coat of acrylic.

 

[yournamehere]

If the siding has primer and factory topcoat of different color or feels dry or chalky, then double coat outside of boards after installation. Just my opinion. You would use large stain brush to backbrush, no?

What is the concern if it is dry and chalky?

I've got a 3in Purdy XL and a 4in Wooster brush.

 

[PressurePros]

What if the backside only has primer? Just found out from the supplier that this is the case. Only the frontside has a top coat of acrylic.

I still say it would be fine. I am not a fan of coating all sides of wood. If not exposed to sun or weather directly, there are not enough benefits to make the time and labor investment worthwhile. In some cases i could argue that it is actually detrimental.

 

[slinger58]

I still say it would be fine. I am not a fan of coating all sides of wood. If not exposed to sun or weather directly, there are not enough benefits to make the time and labor investment worthwhile. In some cases i could argue that it is actually detrimental.

Just curious, when would it be detrimental?

 

[straight_lines]

Its always been traditional to back prime exterior wood, sometimes even double coat it or dipping if its shakes was the preferred system.

I have seen houses with really tough coastal exposures still holding up well after many years done like this. In fact the houses built during that time its the nails that will ruin the finish first.

 

[DeanV]

U.S. Forestry studies say to back prime as well.

 

[Damon T]

Yup. But even if it's just back primed youre ahead of the game. You'll be golden.

 

[yournamehere]

Thanks for the feedback everyone.

 

[NACE]

Back priming has been a prep standard for years. It creates dimensional stability in wood. Dimensional stability is a measurable coefficient of expansion and contraction on a given species of wood that will determine the length of time a coating system will last. If wood is kiln dried to 8-12 % MC, then coating all six sides will maintain that MC and minimize expansion and contraction across the grain.

Back in the OLD days we would back prime cedar clapboard with aluminum paint or long oil primers. Felt was used as a house wrap and tended to cause condensation on the back of boards which increased the stress on the outside paint.

These days with much greater ring orientation and fast growth tress in addition to Tyvek type wraps, pre-priming is even more critical for coating systems long term success.

My mentor and Swedish apprentice who was a VERY critical perfectionist always bought his claps "from the North Side of the Saco River." "Don't give me that faster growing crap from the south side, I don't want to see any growth rings."

That is how he ordered lumber. We back primed them in the barn, stacked them on racks, and Installed them in the spring. Don't see that anymore.

Sent from my iPhone using PaintTalk

 

[Damon T]

Yup you sure don't see that anymore!