Adding support to a deck

[atgcpaul]

The home inspector pointed out some issues with the deck.  The beam (two 2x8s) is sistered and through bolted to the face of the posts instead of resting on top.  I can fix that.

The one that has me scratching my head is the ledger attachment to the house.  According to him there aren't enough bolts securing the deck ledger to the house.  It's a cinderblock foundation, though, so adding new bolts gets tricky with very few options from what I am finding.  It looks like a poured foundation, but it's just nicely parged. There's a crawlspace under the house, but we didn't verify if the existing bolts go straight through or not.

Instead of adding bolts, I'm thinking about adding several concrete pier blocks a foot or two away from the house, then 4x4 posts topped with a beam that sit underneath the existing joists.  That would at least provide support from below, but I am also concerned about the deck pulling away from the house.  Without adding bolts, how would I solve that issue other than to actually sink posts down into the ground?

Would I actually make things worse for the foundation with this approach?  Imagine if there was frost heave under the blocks and now my extra supports are actually pushing up on the deck, but it's rigidly bolted to the house.  Could that crack my foundation?

Thanks,
Paul

   

[Cooler]

Get some 12" or longer galvanized threaded rods and a long carbide tipped drill bit.  Drill thorough both walls of the cinderblock and using large washers at both ends through bolt the ledger board.

Zinc plated is easy to find; hot dipped is preferred.

Lowes sells these unfinished.  If you use them, then dip them in rustoleum primer and then paint.  After bolting it in place, touch up the  paint.

https://www.lowes.com/pd/Steelworks-1-2-...od/3128227

[Roly]

The home inspector pointed out some issues with the deck.  The beam (two 2x8s) is sistered and through bolted to the face of the posts instead of resting on top.  I can fix that.

The one that has me scratching my head is the ledger attachment to the house.  According to him there aren't enough bolts securing the deck ledger to the house.  It's a cinderblock foundation, though, so adding new bolts gets tricky with very few options from what I am finding.  It looks like a poured foundation, but it's just nicely parged.  There's a crawlspace under the house, but we didn't verify if the existing bolts go straight through or not.

Instead of adding bolts, I'm thinking about adding several concrete pier blocks a foot or two away from the house, then 4x4 posts topped with a beam that sit underneath the existing joists.  That would at least provide support from below, but I am also concerned about the deck pulling away from the house.  Without adding bolts, how would I solve that issue other than to actually sink posts down into the ground?

Would I actually make things worse for the foundation with this approach?  Imagine if there was frost heave under the blocks and now my extra supports are actually pushing up on the deck, but it's rigidly bolted to the house.  Could that crack my foundation?

Thanks,
Paul

 Are the existing bolts going into the cinderblocks or a rim joist behind the ledger board ?   Check what the elevation of the deck is in relation to the house floor.  Roly

[Cooler]

I rebuilt my deck over a period of four years, first replacing rotted joists, and then replacing and beefing up others and finally putting on fresh decking and railing.  The reason for that was I was able to repair the existing deck, but I was told that I could not build a new one and meet code. 

In any event the ledger board was attached with on bolt every 4 feet.  That seemed wholey inadequate and I added two bolts ever two feet.  These were 1/2" bolts. 

It is hard to criticize a structure that stood for 48 years without failing and was only in jeopardy because the Douglas Fir had aged out.  But certainly it would never have met code.  I did through-bolt in two places (through the cinderblock).   I don't know if that is to code, but it seems very secure.   The rest were through bolted through existing structure which was sound.

[jteneyck]

Ask your town for the deck building codes.  They will show you how new decks must be constructed.  Even if yours is grandfathered the current codes will tell you the latest thinking of what's best.  

John

[Snipe Hunter]

If you are trying to satisfy the inspector, you'll have to do one of two things. You can't set columns on deck blocks in DC.

1. In DC, the posts would have to set on footers. A "footer" in DC is 6" thick concrete below the frost line, 16" in Diameter. So, you'd have to dig 16" diameter holes below the frost line and pour in at lease 6" of concrete. The post can sit on the concrete and back fill or pour concrete to the top of the hole and sit the post on it. The post has to be anchored to the concrete if it's above ground.

2. It would be easier to drill into the concrete and set more anchors.

Now... if you want to get technical... find out what the code was when the deck was built. That's the code it has to meet or exceed. Not today's code.

[Snipe Hunter]

 Are the existing bolts going into the cinderblocks or a rim joist behind the ledger board ?   Check what the elevation of the deck is in relation to the house floor.  Roly

+1
If there's a door leading to the deck, I highly doubt it's sitting on the concrete foundation. More likely it's sitting on a wood rim joist and the ledger board is bolted to the rim joist.

There are self tapping anchor bolts designed specifically for screwing in a ledger board.  Just shoot one in between every joist and the inspector should be satisfied. Stagger them, one up and the next one down. And, I can tell you that he probably won't be back because the buyer won't want to pay him to coma back.

[atgcpaul]

If you are trying to satisfy the inspector, you'll have to do one of two things. You can't set columns on deck blocks in DC.

1. In DC, the posts would have to set on footers. A "footer" in DC is 6" thick concrete below the frost line, 16" in Diameter. So, you'd have to dig 16" diameter holes below the frost line and pour in at lease 6" of concrete. The post can sit on the concrete and back fill or pour concrete to the top of the hole and sit the post on it. The post has to be anchored to the concrete if it's above ground.

2. It would be easier to drill into the concrete and set more anchors.

Now... if you want to get technical... find out what the code was when the deck was built. That's the code it has to meet or exceed. Not today's code.

+1
If there's a door leading to the deck, I highly doubt it's sitting on the concrete foundation. More likely it's sitting on a wood rim joist and the ledger board is bolted to the rim joist.

There are self tapping anchor bolts designed specifically for screwing in a ledger board.  Just shoot one in between every joist and the inspector should be satisfied. Stagger them, one up and the next one down. And, I can tell you that he probably won't be back because the buyer won't want to pay him to coma back.

It's in Frederick county but their deck guidelines seem to be about same as DC.  I haven't been to the property in almost 3 weeks (we close on Monday) so I'm just working off memory.  The deck is at the same height as the finished floor in the house so you're right that there must be a rim joist for me to bolt into.  Fingers crossed.

This was a to-do item for the seller, but their agent messed up and they never countered which means they basically agreed to do all the repairs per the contract.  However, with the seller out of state now, the appraisal coming in lower than they needed and with us negotiation closing costs, too, their agent agreed to eat the cost of the repairs from their commission by giving me money to do the fixes myself.  Looks like I might come out ahead.

Thanks,
Paul

[Snipe Hunter]

It's in Frederick county but their deck guidelines seem to be about same as DC.  I haven't been to the property in almost 3 weeks (we close on Monday) so I'm just working off memory.  The deck is at the same height as the finished floor in the house so you're right that there must be a rim joist for me to bolt into.  Fingers crossed.

This was a to-do item for the seller, but their agent messed up and they never countered which means they basically agreed to do all the repairs per the contract.  However, with the seller out of state now, the appraisal coming in lower than they needed and with us negotiation closing costs, too, their agent agreed to eat the cost of the repairs from their commission by giving me money to do the fixes myself.  Looks like I might come out ahead.

Thanks,
Paul

The buyer should fire their agent. The agent is covering the costs so he/she doesn't get sued. Can't stand dealing with lousy agents. Part time agents, relatives, rookies, for-sale-buy-powner etc. Nothing but problems. I'm working with one today.

[Snipe Hunter]

It's in Frederick county but their deck guidelines seem to be about same as DC.  I haven't been to the property in almost 3 weeks (we close on Monday) so I'm just working off memory.  The deck is at the same height as the finished floor in the house so you're right that there must be a rim joist for me to bolt into.  Fingers crossed.

This was a to-do item for the seller, but their agent messed up and they never countered which means they basically agreed to do all the repairs per the contract.  However, with the seller out of state now, the appraisal coming in lower than they needed and with us negotiation closing costs, too, their agent agreed to eat the cost of the repairs from their commission by giving me money to do the fixes myself.  Looks like I might come out ahead.

Thanks,
Paul

The buyer should fire their agent. The agent is covering the costs so he/she doesn't get sued. Can't stand dealing with lousy agents. Part time agents, relatives, rookies, for-sale-buy-owner etc. Nothing but problems. I'm working with one today.