Repair Joists

How to repair wooden joists

Property Repair Systems - 01626 331351 - speak to real people about resin repair of joists

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How to repair timber Joists

This project is presented by Property Repair Systems. We show you how to make Structural repairs to Joists inside buildings without removing either a ceiling or a floor, from above, below or from one side.

Definition of a Joist

"spanning timbers that jointly support a floor." (Definitions may vary regionally, as may the spelling)

Joists share the load of a floor and standard calculations cover Domestic Loadings - see TRADA Tables.

Joists rotted in a wall, with a llath and plaster ceiling beneath

First Floor Joists in a Party Wall - rotted ends embedded,

Lath and Plaster ceiling in place.

Common Location in Buildings

Floors at all levels - spanning across the rooms in either direction.

Decay causes

Outside walls - raised ground levels, blocked or damaged gutters and downpipes, blocked air bricks, water leaks.

Inside walls - lack of ventilation, sub site soil touching the joists, condensation, water leaks

Wet rot and insect attack then destroy the bearing ends.

Dry Rot in a floor joist and wall plate.

Dry Rot in Joists sitting on a timber Wall Plate

Insect attack in a beam end - dust is the so called 'frass'

Insect damage in a Joist

Other Factors often seen on Survey

Party Wall - sharing guttering and downpipes, differing

internal ground levels, water leaks.

Cast iron downpipes frequently crack and corrode

Cast iron downpipes crack and corrode


Information required from Survey of Joists

Access for Repair - usually from the top, but may be considered from beneath (hardest physically for the Technician), or from the side.

Note - check the two neighboring properties for similar decay. Compression during rotting often causes timber floors to sag or bounce. Look for rot in the skirting boards - shrinkage or bowing..

Size - width, depth, length, bearing support length

Number - they may vary in size

Timber type - softwood (Pine) or hardwood (Oak), not known

Decay type - wet rot, insect attack (CFB, DWB or Longhorn), Dry rot

Amount to cut off - drill test holes if possible, or tap with a hammer

Final appearance required - visible but painted, decorative natural finish, hidden

Handed - a sketch is useful, with dimensions


Repair Options for Joists

Repair Types - solid resin or Timber Resin Splice (TRS)

Most popular access Types - top slot, side slot, bottom slot

TRS Types - Top Slot = Type C, Side Slot = Type D, Bottom Slot = Inverted Type C

Special situation - above a valuable ceiling - often made of lath and plaster - consider a Type C45 - it has a 45 degree face angle.

45 degree face Timber Resin Splice joist

.Example of a 45 degree face angle Timber Resin Splice - TYPE C45

45 degree faced TRS in place with resin having been poured - note that the ceiling has not been disturbed.


Photo Gallery for Bressumer Repairs by TRS Type

Type A - Solid Epoxy Resin - removable shuttering - drilling up the end grain of the Parent timber on Site

Type B - Solid Epoxy Resin - permanent shuttering - drilling up the end grain of the Parent Timber on Site

Type C - Timber Resin Splice supplied with fitted bars - Top Slot(s) in the Parent timber.

Type C45 - Timber Resin Splice supplied with fitted bars - 45 degree face angle, Top Slot(s) in the Parent timber

Type D - Timber Resin Splice supplied with fitted bars - Side Slot(s) in the Parent timber

Type E - Timber Resin Splice supplied with Top Slot(s) - drill holes up the end grain of the Parent timber.

Type F - Timber Resin Splice supplied with Side Slot(s) - drill holes up the end grain of the Parent timber.

Type G - Timber Resin Splice supplied with Top Slot(s) - cut Top Slot(s) in the Parent timber.

Type H - Timber Resin Splice supplied with Side Slot(s) - cut Side Slot(s) in the Parent timber.


Heritage Considerations for repairing Joists

Repair Type - a Conservation Officer will generally prefer a Timber Resin Splice over a Solid Resin Repair

David Moore holding his first Timber Resin Splice

TRS Type - a Conservation Officer will generally prefer least damage to the parent timber, so TRS Types E (Top Slot) and F (Side Slot) may be offered, in which the slots are created during Manufacture in the new timber and the Technician drills holes up the end grain of the Parent. This is only feasible if the cut off length is at least 600mm.

TRS Type E - cut off the rotten endTRS Type E - drill holes up the end for bars to be bonded intoTRS TYpe E - bars bonded into place

TRS Type E - TRS in place, open top slot or slotsTRS Type E - pouring Structural epoxy Resin into the top slot

TRS Type E Steps - Technician has to drill up the end grain, so needs good clearance to the wall.


More unusual Timber Resin Repair types

Mouldings - sometimes found on the visible decorative faces or edges of exposed Joists


Structural Calculations for Repairing Joists

Free of charge - our Design and a Check Calculation - not Insurance Indemnified - we are not Structural Engineers - same day service

Chargeable - independent Structural Engineer - ask for one of our Forms - Indemnified by a Qualified Structural Engineer - allow at least 5 working days.

Bressumer Structural Data Collection Form - click here for the Form used when we submit your Beam Repair to a Structural engineer.


Epoxy Resins for Repairing Joists

To buy resins - visit our Resins Shop

Sealing beam end face to a TRS or to seal Shutter Boxes - Quick Setting Wood Filler

Pouring into Shutter Boxes (Type A or Type B) and Top Slots (Type C, E) - Structural Epoxy Pouring Grout

Injecting into Side Slots (Type D and Type F) - Structural Epoxy Pouring Grout plus 1 litre Cartridges and Skeleton Gun

Bonding Bars into timbers on site - for Solid Resin Repairs, Type A and Type B and TRS Timber Kits Type E and Type F - Thixotropic Epoxy Injection Resin plus 400cc Cartridge Kits and Skeleton Gun, with extension tubes for the Cartridges.


Bars used for Repairing Joists

Bars fitted to TRS Units - Zinc Plated High Tensile Grade 8.8 Steel Allthread

Couplers - available for joining threaded bars in some applications

Bars fitted on Site - either Zinc Plated High Tensile Grade 8.8 Steel Allthread or Epoxy-Glass Bar


Types of Wood used for Timber Resin Splice Joist Repair Kits

Standard Kiln Dried Softwood (Pine) - white or Redwood Pines, Strength Graded C24

Non standard Kiln Dried Softwood (Southern Yellow Pine, Douglas Fir) - yellow or red striped Pines, Strength Graded C24

Non standard Kiln Dried Hardwood (Oak) - English or American Oaks, not Strength Graded

Non standard Air Dried Hardwood (Oak) - English Oak, will contain insect holes, shakes and splits, will not be dimensionally stable, may shrink, twist and split further in service.


Special Tools for Repairing Joists - we hire these tools

Cutting Slots - Low Speed, High Torque , reversible electric drilling machine (minimum power - 1000 watts), in conjunction with fully fluted wood Augers

Drilling Holes up the ends of joists - Low Speed, High Torque , reversible electric drilling machine (minimum power - 1000 watts), in conjunction with fully fluted wood Augers

Injecting into Side Slots (Type D and Type F) - 1 litre Skeleton Gun

Bonding Bars into timbers on site - for Solid Resin Repairs, Type A and Type B and TRS Timber Kits Type E and Type F - 400cc Skeleton Gun


Manufacturing Time for Timber Resin Splice Joist Repair Kits - minimum

Made in standard Kiln Dried Softwood (Pine) - 3 working days, plus 2 working days for delivery

Made in non standard Kiln Dried Softwood (Southern Yellow Pine, Douglas Fir) - 5 working days, plus 2 working days for delivery

Made in non standard Kiln Dried Hardwood (Oak) - 7 working days, plus 2 working days for delivery

Made in non standard Air Dried Hardwood (Oak) - 21 working days, plus 2 working days for delivery

Elm is also available to Special Order - expensive.


Drawings of installation steps for Timber Resin Splice Joist Repair Kits

Type A - Solid Epoxy Resin - removable shuttering - drilling up the end grain of the Parent timber on Site

Type B - Solid Epoxy Resin - permanent shuttering - drilling up the end grain of the Parent Timber on Site

Type C - Timber Resin Splice supplied with fitted bars - Top Slot(s) in the Parent timber.

Type D - Timber Resin Splice supplied with fitted bars - Side Slot(s) in the Parent timber

Type E - Timber Resin Splice supplied with Top Slot(s) - drill holes up the end grain of the Parent timber.

Type F - Timber Resin Splice supplied with Side Slot(s) - drill holes up the end grain of the Parent timber.

Type G - Timber Resin Splice supplied with Top Slot(s) - cut Top Slot(s) in the Parent timber.

Type H - Timber Resin Splice supplied with Side Slot(s) - cut Side Slot(s) in the Parent timber.


Method Statements for Timber Resin Splice Joist Repair Kits

Type A - Solid Epoxy Resin - removable shuttering - drilling up the end grain of the Parent timber on Site

Type B - Solid Epoxy Resin - permanent shuttering - drilling up the end grain of the Parent Timber on Site

Type A and B Modified - Solid Epoxy Resin - side slots in the Parent Timber due to lack of cutoff space to end drill

Type C - Timber Resin Splice supplied with fitted bars - Top Slot(s) in the Parent timber.

Type D - Timber Resin Splice supplied with fitted bars - Side Slot(s) in the Parent timber

Type E - Timber Resin Splice supplied with Top Slot(s) - drill holes up the end grain of the Parent timber.

Type F - Timber Resin Splice supplied with Side Slot(s) - drill holes up the end grain of the Parent timber.

Type G - Timber Resin Splice supplied with Top Slot(s) - cut Top Slot(s) in the Parent timber.

Type H - Timber Resin Splice supplied with Side Slot(s) - cut Side Slot(s) in the Parent timber.


Download Data Sheets and Safety Data Sheets for Resins

Structural Epoxy Pouring Resin and Grout - for pouring into slots and into cartridge tubes for injection - Data Sheet - Safety Data - Activator

Safety Data - Base - Safety Data - Powder

Thixotropic Epoxy Injection Resin - for injecting holes using 400cc cartridge tubes - Data Sheet - Safety Data Sheet Activator - Safety Data Sheet Base

Mouldable Epoxy Putty - for filling defects - Data Sheet - Safety Data Sheet


Where to find more reading and photographs of Timber Resin Repairs

www.timber-repair.co.uk - how to repair timber joists

Timber Repair Review 1 - Timber Repair Review 2 - call us for the printed versions - 01626 331351

TRADA Eurocode - resin repair technical report by the Timber Research and Development Association

www.joist-repair.co.uk - how to quickly repair joists and beams of any size


Timber Decay Links for photographs of rots and insect damage

www.dryrot.biz - how to kill Dry Rot in buildings

www.woodworm-info.co.uk - how to kill and prevent woodworm and death watch beetle

www.woodworm-expert-advice-forum.org.uk - all your questions and our answers about woodworm damage and treatment


Technical Help for repairing Joists

Property Repair Systems expert staff can help you with all kinds of timber repairs and are more than happy to give further information and advice.

Call 01626 331351 or E: Mail us help@propertyrepairsystems.co.uk


Timber Beam Repairs | Contact | About Us | About the Author | Index Page


 

Property Repair Systems

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Site written by: David Moore

David Moore, B.A. (Hons.), C.T.I.S., C.R.D.S. Technical Author

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Other Property Repair Systems Sites:

www.boron.org.uk - how to use Boron based insecticides/fungicides to treat timber rots and insect attack

www.dampness-info.co.uk - how to treat penetrating dampness in walls and plaster

www.deck-treatment.co.uk - how to treat patio decks and yacht decks

www.dryrot.biz - how to kill Dry Rot in buildings

www.drywallandfloor.co.uk - membranes for lining damp walls, floors, basements and cellars

www.fire-door-paint.co.uk - upgrade doors to 30 minutes fire resistance

www.joist-repair.co.uk - how to quickly repair joists and beams of any size

www.propertyrepairsystems.co.uk - our Home Site

www.steel-fire-paint.co.uk - treat steel with Intumescent Paint to provide fire protection

www.timber-repair.co.uk - how to repair timber beams

www.woodworm-info.co.uk - how to kill and prevent woodworm and death watch beetle

www.woodworm-expert-advice-forum.org.uk - all your questions and our answers about woodworm treatment DIY