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 Troubled Houses - A Home Owner's Resourcesm - Decks

We see many interesting adverse conditions during our inspections, partly because of the unlimited number of ways people can mess up a house, but also because we do a thorough inspection to reveal these adverse conditions. We hope these stories help home owners avoid these costly conditions by learning about causes, preventions, and remedies. A home purchase can create opportunities for the new owner to improve the home, possibly increasing its value, durability, and usefulness.

NOTICE TO BUYERS & SELLERS: This site does NOT encourage or discourage the purchase of any individual house, or style, age, location, or condition of house.  Conditions shown and/or described in the following articles may have been remedied at the house where these conditions were found.  These conditions typically can be remedied by qualified contractors. The presence of these conditions in any house is comparable to any other real estate consideration such as price, size, or location.  Consult a qualified home inspector before purchasing any house, and consult a qualified real estate agent for more information on how to handle a real estate transaction where adverse conditions are reported in a home inspection.   This site does not describe any house by address or knowingly show a readily identifiable exterior image.  Further, no home actively listed for sale on the Twin Cities MLS will be described on these pages at the time the article is posted.

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Click here to learn more about our services, which now include IR Thermography, radon testing, and carbon monoxide tests. All photos copyright Roger Hankey, ASHI Certified® Inspector. All rights reserved. Licenses to use these copyrighted images can be arranged by contacting rhankey@hankeyandbrown.com

"Troubled Houses - A Home Owner's Resource" is a SERVICE MARK of Hankey & Brown Inspection Service Inc.  Click here for the list of topics and all articles in this resource.

Is your deck built properly?  Click here for more information.

We offer deck inspections for home owners.  Shown below are examples of what we find.
     Very Insecure Deck railing
    Potential deck collapse averted by home inspection
    Details Matter:    A screwed up deck
    Faith in Bolts -  Deck beam
     Double decay - Wood deck built atop a timber wall

Clear View Deck Railing – It’s what you don’t see that matters

This 4 year old wood frame deck has a beautiful clear panel railing system that overlooks a lake and wetland.

(C) 2015 HankeyandBrown.com. Deck with clear panel railing Troubled Houses photo by Roger Hankey, ASHI Certified Inspector Eden Prairie, MN

The deck planking is a synthetic wood composite of extruded planks with a wood grain top surface and an extruded ribbed “m” shape underneath.

(C) 2015 HankeyandBrown.com. Large deck with clear panel railing. Troubled houses photo by Roger Hankey, ASHI inspector in Eden Prairie, MN

The deck rail posts are secured with four fasteners in a welded metal flange at the base of each post.  The railings moved easily with hand pressure applied to the toprail.

                                                (C) 2015 HankeyandBrown.com Inadequate attachment of deck post flange for large deck with clear panel railing. Troubled Houses photo by Roger Hankey, ASHI inspector in Eden Prairie, MN

Unfortunately, the deck builder failed to realize the inherent weakness of the deck planking as an attachment point for the flange fasteners. Each flange had only two of the four screws into the deck framing. The other two screws went into the deck planks, often into the thinnest portion of the planks.

(C) 2015 HankeyandBrown.com Deck rail post flange with only 2 of 4 fasteners into solid wood. Post moves easily under hand pressure. Troubled Houses photo by Roger Hankey, ASHI inspector in Eden Prairie, MN

The railings on the stairs were about the same. Two screws at each rail post flange missed the stair framing and went into the tread planks only. Also, the riser material was not suitable for exterior use and was already water damaged.

(C) 2015 HankeyandBrown.com Deck stair rail post flange with only 2 of 4 fasteners into solid wood. Post moves easily under hand pressure. Troubled Houses photo by Roger Hankey, ASHI inspector in Eden Prairie, MN

Our report listed the entire deck railing system as an adverse condition since the railing attachment was not consistent with good and established practice and has a potential for failure under lateral loading.   We recommended immediate correction by a qualified deck builder. One possible remedy would be to remove all the fasteners that go into deck planks only, install solid wood blocking below the deck at each post location and re-install the screws into the solid wood. Alternatively, a bolt and large washer system might work, but the goal is to achieve a deck railing system that can withstand a 200 lb. lateral force applied at any point along the top of the railing.

For more information on deck railing inspections see the North American Deck and Railing Association (NADRA) web site at http://www.nadra.org/consumers/deck_inspections.html

Deck framing and railing connections are often made stronger with the use of metal fasteners made by Simpson StrongTie or DeckLok.  Both manufacturers websites include good illustrations on deck construction.    Another resource for good deck construction methods is the American Wood Council.  They have a Prescriptive guide for deck construction.

Potential deck collapse averted by home inspection

(C) 2015 HankeyandBrown.com Large wood deck and railing. Found to have a high potential for collapse due to improper attachment to house.  Troubled Houses photo by ASHI Certified Inspector Roger Hankey of Eden Prairie, MN

This beautiful deck is attached to the rear of a lovely suburban two story home built in 2003 (deck built 2004).  Initially, our inspection revealed a common adverse condition in the deck railing.  The railing was comprised of metal grills between wood 4x4 posts.  Unfortunately the posts were notched and bolted to the frame through the notched portion.

(C) 2015 HankeyandBrown.com Deck rail post, notched and bolted (very weak). Troubled Houses photo by Roger Hankey, ASHI Certified Inspector in Eden Prairie, MN

This creates a very weak post that has a high potential for splitting at the notch.  This type of post has been thoroughly tested at Virginia Tech and found to failure the strength requirements for deck railings.
Failed Deck Rail Posts

We became more concerned when we examined the unfinished basement wall near the deck and saw large lag screws penetrating into the rim.     

(C) 2015 HankeyandBrown.com Deck ledger lag screws, improperly located in OSB rim (not into solid wood. Troubled houses photo by Roger Hankey, ASHI Certified Inspector in Eden Prairie, MN

We do not normally see the interior ends of bolts or lag screws used for deck ledger attachment, so this caught our eye and lead us to examine the ledger attachment more closely.

(C) 2015 HankeyandBrown.com Deck ledger attachment with improperly located lag screws (not into solid wood at interior). Troubled Houses photo by Roger Hankey ASHI Certified Inspector in Eden Prairie, MN
The exterior view indicated that a reasonable number of lag screws had been used to secure the ledger board to the house, but we were not certain that those screws were into any suitable structural member.  We returned to the inside and cut a test hole into the foil faced foam insulation in the rim to determine the material behind the ledger board.

(C) 2015 HankeyandBrown.com OSB rim between deck ledger board and rigid foam insulation.See lag screw at upper left. Improper attachment.  Troubled Houses photo by Roger Hankey, ASHI Certified Inspector in Eden Prairie, MN
We measured the top plate of the wall and the insulation thickness and determined that the material shown in the insulation cutout was 1/2 inch oriented strand board (OSB).  Therefore, the lag screws were providing very little strength to hold the deck ledger (and deck) to the house.  Good and established practice for deck ledger attachment in this case would have been to install the lags screws into the ends of the wood web floor trusses. (If approved by the wood truss fabricator). 

In fact, we later learned that this plan had been approved by the truss fabricator and the lags screws were simply installed without checking that they were installed into the truss ends.  The deck had passed a municipal inspection with this serious weakness.  Our customer requested a correction and additional lag screws were installed into the ends of the trusses.  Click here to read the deck post testing article from Virginia Tech.      

Details Matter:    A screwed up deck

 (C) 2015 HankeyandBrown.com 4 deck joist hangers with screws Trouble houses photo by Roger Hankey, ASHI Certified Inspector in Eden Prairie, MN

     This deck ran the entire rear wall of a house.  See the detail photos.

3/4 inch screw from joist hanger Troubled Houses (C) 2009 www.HankeyandBrown.com ASHI Certified Inspectors, Eden Prairie, MN   Joist hanger improperly fastened with screws Troubled Houses (C) 2009 HankeyandBrown.com ASHI Certified Inspectors, Eden Prairie, MN 
Screw taken from a joist hanger                                     Detail of joist hanger & screws

Nearly all the joist hanger fasteners were 3/4" sheet metal screws, creating a weak deck-to-house connection with a high potential for collapse.  Our customer was advised to consult a qualified carpenter for immediate correction.  See http://www.safestronghome.com/deck/

Faith in Bolts -  Deck beam

         Wood deck and steps Wood deck beam supported by bolts Troubled Houses (C) 2010 www.HankeyandBrown.com ASHI Certified Inspectors, Eden Prairie, MN        Wood deck beam improperly supported by bolts only Troubled Houses (C) 2010 HankeyandBrown.com ASHI Certified Inspectors, Eden Prairie, MN
This deck looks useable from a distance, but up close it has an important structural element that is not correctly constructed.  The deck beam, composed of two 2x10's is not bearing on the column.  Rather the 2x10's are BOLTED to the sides of the columns.  Therefore the deck is supported by a few bolts rather than on a continuous load path (wood on wood on concrete footing). 

Deck structure - Decayed frame on top of decayed timber

  Deck bearing on a decaying wood timber retaining wall. (C) 2011 HankeyandBrown.com Troubled Houses photo by Roger Hankey ASHI Certified Inspector in Eden Prairie, MN
The owner of this 1985 built home was informed by a prepurchase inspection that the deck and screen porch below had some structural concerns.  Our role was to further diagnose those conditions.  The photo above shows the deck with clear panel railings, screen porch below the deck, and timber retaining wall supporting the deck and the fill beneath the porch. 
 
  Deck column bearing on a decaying wood timber retaining wall. (C) 2011 HankeyandBrown.com Troubled Houses photo by Roger Hankey ASHI Certified Inspector in Eden Prairie, MN
The supporting columns for the deck bear directly atop the 25 year old timber retaining wall which has many decayed timbers.  This decay was particularly troubling at the uphill end of the wall.

   Detail of deck column bearing on a decaying wood timber retaining wall. (C) 2011 HankeyandBrown.com Troubled Houses photo by Roger Hankey, ASHI Certified Inspector in Eden Prairie, MN
This column bears on the decayed end of the timber wall.  The column base is also decayed.  The column has moved and tilted as shown below. 

Tilted deck column bearing on a decaying wood timber retaining wall. (C) 2011 HankeyandBrown.com ASHI Certified Inspectors in Eden Prairie, MN Detail of tilted deck column bearing on a decaying wood timber retaining wall. (C) 2011 HankeyandBrown.com Troubled Houses photo by Roger Hankey, ASHI Certified Inspector in Eden Prairie, MN

The deck also had water damage/decay in the beams that sat atop these columns, due in part to the lack of a rain gutter on the rear eave above the deck.

 Wood deck beneath an unguttered roof. (C) 2011 HankeyandBrown.com Troubled Houses photo by Roger Hankey, ASHI Certified Inspector in Eden Prairie, MN Decayed beam of a wood deck beneath an unguttered roof. (C) 2011 HankeyandBrown.com Troubled Houses photo by Roger Hankey, ASHI Certified Inspector in Eden Prairie, MN
The deck railing posts were fastened to the deck with 4 screws through the white metal base flanges.  The two inner screws in each flange penetrated the deck boards only, making the railing extremely weak. (See similar case described above).  Our recommendations were to consult an engineer specializing in retaining walls and a qualified carpenter to replace all decayed wood.  Ideally, the deck should bear on concrete footings independent of the retaining wall.   A rain gutter on the rear eave would reduce the potential for water damage to the house and deck.  Click here for more information on this topic and a brochure on proper deck construction from the American Wood Council.    Return to top of article list.