Replies

1. 
   RichBeckman | Jan 18, 2005 08:41pm | #1

   If you don't get any good answers here, you should ask this at Breaktime.

   "Additionally, the original balloon framing allowed moisture that did get past the siding to run down inside the wall and out at the brick foundation."

   In other words, it worked great. Water will always get behind the siding and the wall should be designed to deal with that.

   If you are determined to leave the siding alone and you have the interior of the walls open to the back of the siding, I would think of doing something to maintain that drainage plane between the siding and whatever insulation you put in.

   I'm not sure how I would go about that....maybe as simple as running 30# felt cut a bit wider than the bays and stapling the edges to the studs (don't take that as a recommendation...I'm just thinking "out loud")

   Factors that play a role include what kind of insulation are you using (or are you open to suggestions on that) and where are you located (climate is important here).

   Rich Beckman

   Another day, another tool.

1. 
   mcdoak | Jan 19, 2005 01:01am | #2

   Rick,Project is in Oakland, CA. I'm with you on the plan for creating a channel for air and moisture to flow. My current plan is as follows, and I'm open to input:- paint and caulk the hell out of the exterior siding; latex based primer, and water based top coats; consider even caulking horizontally on each run of siding; basically, sealing up the opportunity for water to get into the walls as much as possible.- drill some venting holes (assuming my inspector allows this) in each of the fire blocks and/or plates in each stud bay to allow air circulation and a place for water to run. With a exterior soffit vent at the roof soffit and another vent on the outside at the base of the first floor, I think we can create pathway for exiting moisture and air flow in each bay.- because insulation would effectively block up the airflow in each bay when normally installed, I'm thinking up different ways to hold the insulation back off the inside of the siding. The current thinking is to run a layer of Tyvek on the inside of the wall and staple it 3.5" into the bay (the bays are 4" deep). This would create a 1/2" channel for air and moisture flow. - Next we would then instally normal R13 bat insulation (in plastic sheathing) up against the Tyvek. The idea here is that the Tyvek would prevent moisture (and wind) from coming in contact with the insulation and drywall, yet allow any moisture that did get inside this cavity to wick back out into this newly created 1/2" air/moisture channel.- Lastly, we sheetrock, mud and tape and keep the exterior paint and caulk good and maintained.Please advise your comments.Mike

2. 
   tradesman | Jan 19, 2005 09:16am | #3

   On exterior redwood I have the best results with oil/alkyd resin based primers and topcoat with 2 coats of acrylic latex paint. The oil/alcyd products have better stainblocking ability and water resistance over longer wet periods.  With caulking I would be cautious and not overdoe it. Small amounts and intensly worked into the groves/corners looks and holds up better than fat untreated beads. The combo acrylic/polyurethan caulk will give you best adhesion and wear; it also will act as a bond between boards. Always caulk onto the primed and cured areas and not on bare wood because the caulk will otherwise dry out from behind. Drying time for primer overnight, curing time for caulk overnight; it sounds old fashioned but I get long lasting jobs this way over the last 20 some years.

   The moisture issue has to be thought out because you will deal with moisture from outside and humidity from the inside. Especially the bathrooms and possibly the kitchen might need a moisture barrier from the inside. The barrier should have the ability to slow down the moisture transfer from the inside to the outside. I don't know your climate specifics but here in Colorado we have to deal with extreme temperature differences from day and night time and heat and/or air conditioning will create condensation problems if not taken care of professionally at the time of construction. Just think about the 1896 lifestyle and todays daily bath taking or showering or the creation of heat within the house.

   Well, I'm turning into a writer here; usually tradesman and writer is an oxymoron isn't it?

   Good luck on your project, sounds intriguing to me.

    

1. 
   mcdoak | Jan 20, 2005 04:37am | #4

   thanks for the input...i think we are on the same page re: exterior treatment...still noodling over how to deal with the moisture/air flow...do you have any experience with blown in foam insulation? we are thinking that a foam insulation that is blown in that is impervious to water might be the ticket and negate the need for air and moisture flow...mike

1. 
   tradesman | Jan 20, 2005 06:48am | #5

   I did about 20 framed homes in Europe but it was all new construction. We used borate treated cellulose products or lambs wool products (I think that is the name in English) but neither of them would not be recomendable for your project (water absorption!). What you need is a PU product wich does not absorb water anymore after curing time. There are water- based sprayable PU products on the market but I don't know enough about it. I'm just mentioning this because the water based products are easier to handle than solvent based PU. Polyurethan has superior R-values, does not absorb moisture(very minimal) and the density is outstanding (and can be monitored). Most likely you might contract with a professional installer in this field. I have only worked with rigid PU-foam in precast concrete buildings and the foam is attached on the outside and covered with plaster on  mesh.

   If you go this way(PU) and if you have new quality windows and doors you will be creating an airtight building envelope which needs to be vented. In this case you might get smart about a venting system in time. It could be as simple as an electrical vent for each building area.

   Like I said before, it is an intriguing project! Enjoy and take many pictures.