“Controlling rain is the single most important factor in the design and construction of durable buildings, and in the control of mold” — Joseph Lstiburek
Uncontrolled water and moisture are no friends of structures built by humans, and can easily threaten the durability of any house, old or new, in a very short span of time. Very old homes are particularly susceptible to water damage. Often, this is a consequence of deferred maintenance, which is a euphemism for the neglect that occurs when owners notice problems, but are unable, or unwilling, to invest in making necessary repairs. Other times, it’s simply because no one was paying attention when signs of trouble began to emerge. In my previous article, Humane De-squirel-fication at the Mansfield House, I cited these two sins of omission as being main causes of rodent infestation. And I think it’s fair to say that they lie at the heart of many of the serious problems facing older homes.
Just as with rodent infestation, the Mansfield House likewise has been no stranger to water damage perpetrated by myriad past sins. Although these problems are not my fault, they’re my responsibility to take ownership of and resolve. And I’ve chosen to publicize the situation here, as a warning to others to remain vigilant while caring for an older home, and not to ignore key warning signs. Furthermore, from a home performance and durability perspective, it should be noted that it makes no sense to talk about the finer aspects of managing indoor air quality, air sealing, insulating, HVAC efficiency, etc., etc., when there’s a major bulk water issue looming. Any exterior or bulk water control problems needs to be addressed first, before delving into anything else.
Our recent problems began a few years ago, with a roof leak (an example of sin of omission #2, as no one was keeping an eye on the condition of the roof). A resident caretaker living here at the time delayed reporting this to the owners (a variation of sin of omission #1). So the problem only grew worse. Second floor ceilings were damaged, and some mold formed in the attic. However, the old lime plaster actually held up quite well, and will be fine, following some forthcoming repair work and repainting. For me, this is a testament to the superior building methods of the past, as I doubt modern sheetrock would’ve held up under the same abuse. [Also: did you know that lime plaster sequesters a great deal of carbon dioxide? It's one of the earliest green building materials.]
The previous owners dealt with the water infiltrating the attic by replacing the entire roof, as the previous roof was quite old and deteriorated at that point. However, from this point forward, we’ll be performing an annual roof inspection here (both interior and exterior, using IR thermography, and direct moisture testing at penetrations) so as to catch any small problems before they get bigger.
The next big problem began probably about the same time as the roof leak, when the front and rear gutters were mysteriously removed from the eaves and somehow lost or misplaced. No one can explain how or why this came to be, but none of that matters now. Suffice it to say that this turned into a long-term situation (another example of sin of omission #2), and several years of undiverted rain water caused considerable damage to the house and foundation.
Now, why would rain dripping from the edge of a roof be so problematic? Well, in most typical homes, uncontrolled drainage can erode the soil over time, as well as accumulate in the soil near the foundation and undermine it, especially if the soil is not properly graded or flashed so as to divert water away from the house.
Furthermore, this can lead to moisture infiltrating the basement, and bringing elevated humidity, mold growth, poor indoor air quality, and pests that thrive on moisture, like termites, along with it. But even if there are no obvious grading or soil drainage issues, it doesn’t mean these problems still can’t occur. Prevention is always the most effective and least costly cure, so why even allow the possibility for any of this, when a well-fitted and working gutter system can prevent it?
In the particular case of the Mansfield House, the problems induced by missing rain gutters are even more pronounced because of the house’s architecture and age. The eaves have a very minimal overhang, and, like many houses of its vintage, the exterior walls are not plumb, and all tend to lean inward a bit. This means that uncontrolled rain water dripping from the shingles above the eaves falls directly on to the siding below, as well as on any architectural openings (windows, doors) and elements of trim.
Furthermore, as the Mansfield House is a classic New England saltbox, its rear roof (sometimes referred to as a “lean-to roof”) carries most of the square footage of the entire roof system. On the other hand, the rear exterior wall that the lean-to connects to is quite small in terms of square area. So, a great deal of water is collected by the rear roof, and, without being managed by an adequate gutter system, gets dumped directly on that small exterior wall in the rear.
So just a few years of this activity has resulted in substantial water damage. The two rear window sills had rotted, allowing water to infiltrate the rear wall. This caused staining of interior plaster in the kitchen, and beneath one of the windows, large sections of plaster have cracked and even separated from their lath.
The rear panel door, which is an historic artifact, also suffered considerably, not only from water dripping down from above, but also from water splashing back from the stone walk just beneath the door. The door itself is salvageable, although the entire bottom rail will need to be replaced, and the lower panels restored with some combination of Dutchmans and epoxy.
However, there’s an even more subtle, potential issue with the rear wall, stemming from the current, mechanical state of the cladding itself. Some time this past century, some one (I know not whom, nor when) systematically face nailed all of the clapboards to the sheathing with wire nails. Most likely, this was done as an attempt to straighten and secure the clapboards, many of which were severely cupped, bent, split, or otherwise detaching from the sheathing at the time. Their previous condition is plainly obvious, for example, in a highly detailed photo of the Mansfield House dating back to 1894.
Furthermore, the Mansfield House is sheathed with vertical planks (much as you’d see on an old barn), and the clapboards are fastened across these planks. From a moisture control perspective, this old style of construction is generally fine, as long as there’s a slight gap between the overlapping clapboards to facilitate their ventilation and drying. But whom ever face nailed the clapboards neglected to “sticker” them with small wedges to keep these gaps open, which means there’s a greater potential now for water to be drawn upward, between overlapping clapboards, via capillary action, and far less opportunity for that same water to be subsequently removed via ventilation. Therefore, the clapboards now have a tendency to absorb and hold much more water then they had prior to being face nailed in this manner.
So, the current deluge of water against the rear wall, every time it rains, can now be seen to have even worse consequences than one might’ve initially imagined, all because of the thoughtless manner in which the clapboards were nailed shut. In fact, I contend that the large areas of green mold (or lichen, or what ever you prefer to call it), forming on the rear wall, are there mainly because of the wall’s general inability to ventilate itself dry.
By comparison, the front wall of the Mansfield House has fared much better, mainly because the front roof represents a much smaller percentage to the total roof area, and collects far less rain water than the rear roof. And also because the front of the house has far more exposure to sunlight than the rear. But the front has still suffered, nonetheless. In particular, the stone and concrete infrastructure supporting the front steps and landing has had much of its material eroded away, and the foundation on either side of the front entry has also incurred obvious water damage, most likely due to splashback from the landing itself. The front door had also been consigned to the same fate as the rear door, as the result of this splashback.
Of course, the solution to these problems is to replace all the missing gutters and downspouts (which is what I’m doing right now), quickly followed by remediation of the various, damaged areas.
Furthermore, at some point in the future, I’m planning to carefully “de-clad” each exterior wall of the Mansfield House, construct a continuous and properly flashed drainage plane/capillary break over the plank sheathing, and precisely replace each of the clapboards back in their original locations. Most likely, I’ll have to repeat the face-nailing exercise, as I imagine the clapboards will still misbehave when replaced, but I’ll also incorporate an appropriate, well-supported gap between the clapboards for ventilation. And any further face-nailing will also employ a galvanized version of a traditional, square cladding nail (that is, as long as my local building department allows me to).
The final bulk water control issue here involves controlling run-off from the large retaining wall immediately adjacent to the house and foundation. This wall is laced with a good many 4″ drains, all pointing directly at me like the muzzles of 16 pounders on an ancient Man O’ War fighting ship.
In the short time I’ve been here, I’ve never seen a single drop of fluid expelled from any of them. But there’s evidence of past deluges where run-off seriously undermined my smaller, front rubble wall, just where it connects to the Man O’ War.
There’s about a four or five foot separation between my foundation and the base of the Man O’ War. What I’d like to do here (another future project) is construct a ground flashing system using EPDM sheeting, between my foundation and the Man O’ War. The sheeting would be attached to both the foundation and the retaining wall, just slightly above grade, and form a V-shape down into the ground, with the bottom point of the “V” emptying into a French drain. (Exactly where the end of the French drain would open to, I’m not quite sure yet).
Furthermore, I’d like to construct this ground flashing system all along the perimeter of my foundation, wherever it lies substantially below grade, as well. Of course, how all this turns out is ultimately up to my local building department, the Connecticut DEP, and possibly even the Connecticut SHPO. But this is more or less the proposed plan that I’ll be fleshing out on paper soon, anyway.
Stay tuned for follow-on posts on this topic, including one where I’ll present the results of my systematic mapping of the moisture content of the rear exterior wall, along with a methodology I’ve devised for taking and recording scans of large problem areas. Oh, and those new gutters will be featured at some point, too…