As I do a home inspection, I usually start outside first.
I walk around the house a couple of times, usually before the client arrives.
Making notes, and when we get started, I can explain what I have come up with.
When I saw this I knew we had a problem.
Can you see what it is?
The ends of the decking have been caulked where they abut the house.
And the gaps between the decking boards have also been caulked, outward about 4".
This deck is about 15 years old. That caulking is not so old.
How did I know this was a problem?
From underneath you can see that there is no deck flashing.
The through bolts are rusty and where the hose bib service line exits the house you can clearly see staining.
Is water getting in?
Even not going inside yet I knew that it at least had been.
WATER GETS IN VIA THOSE THROUGH BOLTS AND THAT PLUMBING TUBE.
There is a slight gap between that ledger board (the one you are looking at bolted against the house) and the house itself.
Water wicks inside on those bolts or tubing. It is a regular water highway.
Hence the caulking!
Someone noticed that water had been getting inside and caulked things up. While it is not a permanent solution, it probably worked. But I would know more indoors.
Conveniently the homeowner had removed the insulation there, I guess to handle this problem.
Stains can clearly be seen around the through bolts on the left.
And even though the plumbing tube was caulked inside as well, water was getting in between that stabilizing board and the rim joist that the homeowner actually put a rag there to soak it up!
More staining can be seen to the right.
So this was an active leak.
It was not wet at this time though, even though it had just rained.
So for now the caulking is working, and maybe had been for a number of years.
What would have been best practice?
I have posted this before, but deck flashing is that small piece of bent metal, sometimes called "Z flashing," seen in the circle to the left.
It is installed UNDER the siding and OVER the ledger beam so no water can enter the house behind that ledger beam.
That way the bolts are just that and not waterways.
Many people, homeowners included, have never heard of deck flashing.
I had a homeowner once call me and call me names because I mentioned the lack of deck flashing on his report and said that he had never heard of such a thing and I had "just made up something to put on the report!" Yes, he said that, very loudly!
Deck flashing, had it been present, would clearly have been visible in the second photo above. Caulking would not have been needed.
DECK FLASHING IS BEST PRACTICE!
My recommendation: when you look at the underside of a deck, look for deck flashing. It really does demonstrate the difference between a professional deck installation and one that is not so.
How often do I see it? I don't know, but would guess less than 10% of the time.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560