pocket joist(s) replacement

PA_DIY'er

i tried to do a search on this and didnt come up with what i was looking for.

my wife and i are looking at a house with loads of potential. its a 130 year old stone and mortar home (3500+ sq ft) on over 3/4 of an acre for an attractive price. we knew there would be work needed for the asking price, so now is the time to start looking for the knowledge now that we know what is wrong.

while doing a walkthrough with our agent, i noticed a "bounce" in one of the first floor rooms. after gaining access to the basement/crawlspace, we found that the floor joists are rotten (which i attribute to 130 of being suspended above a dirt floor) and are in need of replacement. they are too far gone for sistering. the house is stone from the basement floor to the roof and the floor joists are set in pockets which appear to have been built around them. original 4x8 or 10 hand hewn logs.

the floor sitting on the joists has a few holes in it around the perimeter, so our thought would be to completely replace the floor as well. i would like to get some advice on the project though, as i have only really heard of pocket joists and never really dealt with them.

i read an article somewhere on the web that said the floor would have to be cut away from the top which would allow the replacement joists to be slid into the pockets from above and then the floor can be replaced. this seems to be an easy enough task, as i have a better than average mechanical skill and have worked on construction sites for about the past 10 years, observing other trades while doing my own (hvac).

my initial thought is to pour a slab over the dirt floor in the basement in order to eliminate the humidity and moisture which contributed to the mess and to use doubled up 2x8 or 10's (will match existing. didnt have a tape on me at the showing) bolted and glued, to replace the old logs.

any advice or criticisms you can offer would be very appreciated. the amount of info on this site is amazing, so im hoping some will find its way here. thanks in advance.

Daniel Holzman

There may be more going on than just a humid basement. I have inspected a number of very old barns and houses that had dirt floors in the basement, and most of them did not have rotten joists. Joists will rot if exposed to wet/dry conditions, but in my experience do not rot simply because the basement is damp. Most basements are damp, simply pouring a concrete floor will not eliminate the dampness, for that you need a dehumidifier in most cases.

I would check very carefully to make sure there are no internal or external leaks, insect infestations, or some other cause of rotten joists. As for replacing them, without detailed photos and a dimensioned sketch it would be impossible to visualize exactly how to remove the old joists, support the structure above, and then replace.

Bud Cline

I agree a damp basement shouldn't necessarily cause the floor joists to rot. Any sign of termites or ants?
Small tunnels or channels or borings or tiny piles of saw dust here and there?


I would first want to know exactly what the foundation walls are sitting on, if anything. You would have to dig down on the inside along an outside wall to determine exactly how the walls were constructed.

The fact that the timber joists are sitting in pockets may also be what is holding the walls in vertical position after all this time. Wholesale removal of the timber joists may cause a wall collapse.

How's that for a start? I know...scary! I'm assuming you guys have deep-enough pockets to take on a structure of this kind and age.

Replacing the floor joists (per se) shouldn't be a major issue. You will need an alignment plan of course.

How about some pictures?

PA_DIY'er

thanks for the replies guys. unfortunately, i dont have any pics because the wife neglected to tell me that she had the camera at a bday party the day before and when i went to take a shot it died on me. didnt see any signs of pests (not to say that they arent there). no dust or holes or anything, but there was eveidence of moisture on the wood and it looked like wet rotten wood ive seen while out camping or hunting.

if we can bring the asking price down to where we want it because of the repairs needed then we will have the means to take care of it. we have a set price we are willing to go to comfortably and then we walk away. it does have a newer in law suite above a block garage that we plan on living in while the main house is repaired and we can begin to use other rooms. i know this is a big undertaking, but as i said, if we can get the price right, it will have a huge return for us. the main house has been vacant for at least a year, and there are broken windows throughout the first floor, and one of the basement windows is gone so i would imagine that the rain has made its way and sat on the floor/carpet and also made its way into the basement for some time, not to mention the snow melts. the foundation looks solid all around the basement perimeter, with no signs of mortar deterioration or loose stones, and the outside appears solid as well, with just a little stucco damage that i believe is from age and poor upkeep.

the good is that the 2nd floor and attic are extremely sturdy. there were area rugs in some of the rooms that we moved aside to reveal nice dry planks with no signs of bounce or giving. the staircases are nice and sturdy and the roof is in better than average condition. we havent had any inspections done yet until we know we are going anywhere with the seller.

and bud, please excuse my ignorance, but what exactly do you mean by an alignment plan? or does that question automatically put me into the "get a contractor" category?

Bud Cline

I'm sure the "joist pockets" are sort of helter skelter simply because timbers were used then apparently packed with cement mortar or something. Once you begin to remove the old timbers the new joists will have to be aligned somehow. That is where a "plan" is necessary. I'm thinking you can't simply pull out a timber and shove in a joist. There will likely be some hammering of old cement and then shimming of the new joists. This is why a photo would be helpful. My imagination may be running wild.